Tait T860 Series II Service Manual
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Tait T860 Series II Service Manual

Tait T860 Series II Service Manual

220-285mhz
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M860-00-Preliminary
T860 Series II
Base Station Equipment
220-285MHz
Preliminary Service Manual
July 1998
M860-00-PRELIM
Copyright TEL
30/06/98

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  • Page 1 M860-00-Preliminary T860 Series II Base Station Equipment 220-285MHz Preliminary Service Manual July 1998 M860-00-PRELIM Copyright TEL 30/06/98...
  • Page 2 Phone: 64 3 348-3301 Phone: 61 7 3865-7799 Fax: 64 3 343-0558 Toll Free: 1800 077-112 Fax: 61 7 3865-7990 Singapore Tait Electronics (Far East) Pte Ltd Beijing 4 Leng Kee Road Tait Mobile Radio (HK) Ltd SIS Building #05-11A Beijing Representative Office...

  • Page 3: About This Manual

    T869 Power Amplifier Copyright All information contained in this manual is the property of Tait Electronics Ltd. All rights are reserved. This manual may not, in whole or part, be copied, photocopied, reproduced, translated stored or reduced to any electronic medium or machine readable form without prior written permission from Tait Electronics Ltd.
  • Page 4 M860-00-Preliminary Table Of Contents This manual is divided into six parts as listed below, with each part being further sub- divided into sections. There is a detailed table of contents at the start of each part and/ or section. Part Title Introduction To Servicing T865 Receiver...

  • Page 5: Table Of Contents

    M860-00-Preliminary Part A Introduction To Servicing This part of the manual is divided into the sections listed below. These sections provide some general and advisory information on servicing procedures, and a brief history of PGM800Win programming software. Section Title Page General Additional Technical Information Caution: CMOS Devices...
  • Page 6 M860-00-Preliminary 30/06/98 Copyright TEL...

  • Page 7: General

    Philips data books covering CMOS devices, or Motorola CMOS data books, Section 5 'Handling', etc. An anti-static bench kit (refer to Figure 1.2) is available from Tait Electronics Ltd under the following product codes: •...

  • Page 8: Caution: Aerial Load

    A1.2 General M860-00-Preliminary conductive conductive rubber wrist strap bench mat to building earth (not mains earth) Figure 1.2 Typical Anti-static Bench Set-up Caution: Aerial Load The equipment has been designed to operate safely under a wide range of aerial loading conditions.

  • Page 9: Mechanical

    Mechanical A2.1 M860-00-Preliminary Mechanical Torx Recess Head Screws Torx recess head screws are becoming the standard screw head type in all T800 Series II equipment, with Pozidriv and Philips recess head screws being used in fewer applica- tions. The Torx recess head has the advantage of improved screwdriver tip location, reducing the chances of screw head damage caused by the driver tip rotating within the recess.

  • Page 10: Pozidriv & Philips Recess Head Screws

    A2.2 Mechanical M860-00-Preliminary Pozidriv & Philips Recess Head Screws Pozidriv and Philips recess head screws will continue to be used in T800 Series II equip- ment in a few special applications. It is important that you use the correct type and size screwdriver for each screw type to avoid damaging the screw head.

  • Page 11: Disassembly/Reassembly

    Mechanical A2.3 M860-00-Preliminary Disassembly/Reassembly 2.3.1 Receivers/Exciters To carry out alignment or change option links, you need to remove only the top cover, i.e. the one adjacent to the front panel handle and on the opposite side to the main D-range connector (D-range 1/PL100). You need to remove the bottom cover to: •...
  • Page 12 A2.4 Mechanical M860-00-Preliminary 30/06/98 Copyright TEL...

  • Page 13: Component Replacement

    Component Replacement A3.1 M860-00-Preliminary Component Replacement Leaded Components Whenever you are doing any work on the PCB that involves removing or fitting compo- nents, you must take care not to damage the copper tracks. The two satisfactory meth- ods of removing components from plated-through hole (PTH) PCBs are detailed below. Note: The first method requires the use of a desoldering station, e.g.

  • Page 14: Surface Mount Devices

    Surface mount devices (SMDs) require special storage, handling, removal and replacement techniques. This equipment should be serv- iced only by an approved Tait Dealer or Subsidiary equipped with the necessary facilities. Repairs attempted with incorrect equipment or by untrained personnel may result in permanent damage. If in doubt, contact your nearest Tait Dealer or Subsidiary.

  • Page 15: Software History

    Software History A4.1 M860-00-Preliminary Software History 28/06/96 PGM800Win Version 1.0 18/08/97 PGM800Win Version 2.00 PGM800Win V1.0 PGM800Win V1.0 is different in concept from DOS versions of PGM800 in that it is Win- dows based. It also includes many new and improved features over DOS versions of PGM800.
  • Page 16 A4.2 Software History M860-00-Preliminary • Extra information that is not stored in the radio (but which is still relevant to the radio) can be saved to a file on disk (e.g. note field, auxiliary pin names, etc.). Note: The data files produced by BASEPROG V1.0, all DOS versions of PGM800, and PGM800Win V1.0 are still compatible with PGM800Win V2.00.

  • Page 17: T865 Receiver

    M860-00-Preliminary Part B T865 Receiver This part of the manual is divided into six sections, as listed below. There is a detailed table of contents at the start of each section. Section Title General Information Circuit Operation Initial Tuning & Adjustment Functional Testing Fault Finding PCB Information...
  • Page 18 M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 19 T865 General Information B1.1 M860-00-Preliminary T865 General Information This section provides a brief description of the T865 receiver, along with detailed speci- fications and a list of types available. The following topics are covered in this section. Section Title Page Introduction Specifications 1.2.1...
  • Page 20 B1.2 T865 General Information M860-00-Preliminary 30/06/98 Copyright TEL...

  • Page 21: M860-00-Preliminary T865 General Information

    The front panel controls include gating sensitivity, line level, monitor volume and a monitor mute switch. The T865 has a width of 60mm and occupies a single space in a Tait rack frame, which has the ability to accommodate up to seven standard modules.

  • Page 22: T865 General Information

    .. negative earth only Polarity Protection .. diode Supply Current: Standby .. 350mA Full Audio .. 750mA Operating Temperature Range .. -30°C to +60°C 1. Additional channels may be factory programmed. Contact your nearest Tait Dealer or Subsidiary. 30/06/98 Copyright TEL...

  • Page 23: Rf Section

    T865 General Information B1.5 M860-00-Preliminary Dimensions: Height .. 191mm Width .. 60mm Length .. 324mm Weight .. 2.13kg 1.2.3 RF Section Frequency Range .. 220-270MHz Type .. dual conversion superheterodyne Frequency Increment .. 5 or 6.25kHz Switching Range .. 4MHz (i.e. ±2MHz from the centre frequency) Input Impedance ..

  • Page 24: Audio Section

    B1.6 T865 General Information M860-00-Preliminary Selectivity: Narrow Bandwidth (±12.5kHz) .. 85dB minimum, 89dB typical Mid Bandwidth (±20kHz) .. 87dB minimum, 90dB typical Wide Bandwidth (±25kHz) .. 90dB minimum, 95dB typical Offset Selectivity (Canada only) .. 20dB Spurious Response Attenuation .. 100dB Intermodulation Response Attenuation: Narrow Bandwidth ..

  • Page 25: Ctcss

    T865 General Information B1.7 M860-00-Preliminary Line Output: Power .. adjustable to >+10dBm Load Impedance .. 600 ohms Distortion (@ -70dBm signal level): De-emphasised Flat ≤2% ≤2% Wide Bandwidth ≤2% ≤4% Mid & Narrow Bandwidth Monitor Output: Power .. 1W Speaker Impedance ..

  • Page 26: Test Standards

    B1.8 T865 General Information M860-00-Preliminary Carrier Mute (Optional): Operating Range .. -115 to -80dBm Hysteresis .. 2 to 10dB Opening Time .. 5ms Closing Time .. 50ms Note: The opening and closing times given above are for the standard set-up (SL210 linked and SL220 not linked - refer to Section 3.3).

  • Page 27: Dti Cept Recommendation T

    T865 General Information B1.9 M860-00-Preliminary 1.2.6.2 DTI CEPT Recommendation T/R-24-01 Annex I: 1988 Technical characteristics and test conditions for radio equipment in the land mobile service intended primarily for analogue speech. Annex II: 1988 Technical characteristics of radio equipment in the land mobile service with regard to quality and stability of transmission.

  • Page 28: Product Codes

    M860-00-Preliminary Product Codes The three groups of digits in the T860 Series II product code provide information about the model, type and options fitted, according to the conventions described below. The following explanation of T860 Series II product codes is not intended to suggest that any combination of features is necessarily available in any one product.

  • Page 29: Standard Product Range

    Standard Product Range The following table lists the range of standard T865 types (i.e. no options fitted) availa- ble at the time this manual was published. Consult your nearest Tait Dealer or Subsidi- ary for more information. Frequency Range (MHz)
  • Page 30 B1.12 T865 General Information M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 31 T865 Circuit Operation B2.1 M860-00-Preliminary T865 Circuit Operation This section provides a basic description of the circuit operation of the T865 receiver. Note: Unless otherwise specified, the term "PGM800Win" used in this and follow- ing sections refers to version 2.00 and later of the software. Refer to Section 6 where the parts lists, grid reference index and diagrams will provide detailed information on identifying and locating components and test points on the main PCB.

  • Page 32: M860-00-Preliminary

    B2.2 T865 Circuit Operation M860-00-Preliminary 30/06/98 Copyright TEL...

  • Page 33: T865 Circuit Operation

    T865 Circuit Operation B2.3 M860-00-Preliminary Introduction Noise Mute Mixer Mixer Limiter Speaker Front 21.4MHz 455kHz Audio Processor 600Ω Line Detector Synthesised Second Local Local Oscillator Oscillator Carrier Mute 12.8MHz Master Oscillator RSSI Figure 2.1 T865 High Level Block Diagram The T865 receiver consists of a number of distinct stages: •...

  • Page 34: Receiver Front End

    B2.4 T865 Circuit Operation M860-00-Preliminary Receiver Front End (Refer to the front end, IF section and audio processor circuit diagrams (sheets 4, 3 and 2 respectively) in Section 6.) Local Oscillator (From Synthesiser) RF In 220-270MHz 2dB Pad Post 4-Pole Harmonic Doublet Doublet...

  • Page 35: Mixer

    T865 Circuit Operation B2.5 M860-00-Preliminary Mixer (Refer to the front end circuit diagram (sheet 4) in Section 6 and Figure 2.2.) IC420 is a high level mixer requiring a local oscillator (LO) drive level of +17dBm (nom- inal). The voltage controlled oscillator (VCO) generates a level of +22dBm (typical) and this is fed to the mixer via a 2dB attenuator pad.

  • Page 36: Noise Mute (Squelch)

    B2.6 T865 Circuit Operation M860-00-Preliminary Noise Mute (Squelch) (Refer to the audio processor and IF section circuit diagrams (sheets 2 and 3 respec- tively) in Section 6 and Figure 2.2.) The noise mute operates on the detected noise outside the audio bandwidth. An opera- tional amplifier in IC390 is used as an active band pass filter centred on 70kHz to filter out audio components.

  • Page 37: Audio Processor

    T865 Circuit Operation B2.7 M860-00-Preliminary Audio Processor (Refer to the audio processor circuit diagram (sheet 2) in Section 6.) From RSSI RSSI Output IF Stage (Optional) PL270 Mute Relay Relay PL250 Carrier Mute Gate Output Noise Mute Rx Disable Rx Disable Timer (Optional Pad) PL260...

  • Page 38: Power Supply And Regulators

    B2.8 T865 Circuit Operation M860-00-Preliminary The audio can also be disabled using the "RX-DISABLE" inputs, pads 225 or 228, having connected the "RX-DISABLE" link between pins 1 & 2 of PL260. An adjustable time delay (RV220) is provided on these lines. In order to disable the audio, either pad must be pulled to 0V.

  • Page 39: Microcontroller

    T865 Circuit Operation B2.9 M860-00-Preliminary Microcontroller (Refer to the microcontroller circuit diagram (sheet 8) in Section 6.) 5V Digital Watchdog Timer Regulator & LVI Reset Watchdog Microcontroller Cavity Channel Select Port 12.8MHz Microcontroller Clock Auxiliary Output Port External Serial Converter Port Audio In CTCSS...

  • Page 40: Synthesised Local Oscillator

    B2.10 T865 Circuit Operation M860-00-Preliminary 2.10 Synthesised Local Oscillator (Refer to the synthesiser circuit diagram (sheet 7) in Section 6 and the VCO circuit dia- gram in Part E.) FREQUENCY SYNTHESISER IC VCO PCB Reference Phase Charge Loop Output Divider Detector Filter Pump...

  • Page 41: Vco

    T865 Circuit Operation B2.11 M860-00-Preliminary 2.11 (Refer to the VCO circuit diagram in Part E.) The VCO transistor (Q1) operates in a common source configuration, with an LC tank circuit coupled between its gate and drain to provide the feedback necessary for oscilla- tion.
  • Page 42 B2.12 T865 Circuit Operation M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 43 T865 Initial Tuning & Adjustment B3.1 M860-00-Preliminary T865 Initial Tuning & Adjustment The following section describes both short and full tuning and adjustment procedures and provides information on: • channel programming • selecting the required audio links • synthesiser alignment •...
  • Page 44 B3.2 T865 Initial Tuning & Adjustment M860-00-Preliminary Section Title Page Noise Mute Adjustment 3.12 3.10 Carrier Level Mute 3.12 3.11 Audio Processor 3.13 3.11.1 Line Amplifier Output 3.13 3.11.2 Monitor Amplifier Output (Speaker Output) 3.13 3.12 RSSI 3.13 Figure Title Page T865 Test Equipment Set-up For Short Tuning Procedure T865 Test Equipment Set-up For Full Tuning &...

  • Page 45: M860-00-Preliminary T865 Initial Tuning & Adjustment

    PCB. Refer to Part C in the T800 Series Ancillary Equipment Service Manual (M800-00-101 or later issue) or consult your nearest Tait Dealer or Subsidiary for further details. 1. Use the "Read Module" function in PGM800Win to find out what the default channel is.

  • Page 46: Test Equipment Required

    B3.4 T865 Initial Tuning & Adjustment M860-00-Preliminary Test Equipment Required You will need the following test equipment: • computer with PGM800Win installed • T800 programming kit • module programming interface (e.g. T800-01-0004 - optional) • 13.8V power supply • digital multimeter •...

  • Page 47: Short Tuning Procedure

    T865 Initial Tuning & Adjustment B3.5 M860-00-Preliminary Short Tuning Procedure Use this procedure only if you want to reprogram the receiver to a frequency outside the 4MHz switching range and do not intend to carry out any other major adjustments or repairs.

  • Page 48: Mute Adjustment

    B3.6 T865 Initial Tuning & Adjustment M860-00-Preliminary Continually decrease the RF level to maintain 12dB sinad. Readjust L410, L420, L460 & L470 to give best sinad. With PL210 and PL220 connected for de-emphasised audio response, the receiver sensitivity should be better than -117dBm, assuming that the audio levels are not being overdriven (refer to Section 3.4.5).

  • Page 49: Rssi (If Used)

    T865 Initial Tuning & Adjustment B3.7 M860-00-Preliminary 3.4.6 RSSI (If Used) Align the receiver as instructed in Section 3.6 and Section 3.7. Apply an on-channel signal from the RF generator at a level of -100dBm with 3kHz deviation (2.4kHz) [1.5kHz] at 1kHz. Adjust RV320 (RSSI level) to give 4.5V RSSI output on pin 5 of D-range 1 (PL100) when measured with a high impedance DMM.

  • Page 50: Audio Processor Links

    B3.8 T865 Initial Tuning & Adjustment M860-00-Preliminary Audio Processor Links 3.5.1 General Use the following table to set up the audio processor to the configuration you require. You should set the audio processor links before carrying out the receiver alignment. The factory settings are shown in brackets [ ].

  • Page 51: Audio Processor Linking Details For Ctcss

    T865 Initial Tuning & Adjustment B3.9 M860-00-Preliminary 3.5.2 Audio Processor Linking Details For CTCSS You must connect the audio processor links correctly according to the CTCSS option used, as shown in the table below. CTCSS Option PL230 PL240 standard, no CTCSS 2 - 3 2 - 3 received CTCSS + speech...

  • Page 52: Synthesiser Alignment

    B3.10 T865 Initial Tuning & Adjustment M860-00-Preliminary Synthesiser Alignment • Ensure that the receiver has been programmed with the required frequencies using PGM800Win software. • Connect a high impedance voltmeter to PL4-1 or the junction of L1 & R1 in the VCO (this measures the synthesiser loop voltage).
  • Page 53 T865 Initial Tuning & Adjustment B3.11 M860-00-Preliminary Note: If a second oscillator is not available, you can connect a frequency counter to IC710 pin 8 (i.e. after the TCXO buffer) via an oscilloscope probe to measure the TCXO frequency directly (12.8MHz). At this point the voltage level is approximately 4V p-p.

  • Page 54: Gating Delay

    B3.12 T865 Initial Tuning & Adjustment M860-00-Preliminary Gating Delay Two solder links (SL210 & SL220) are provided on the bottom of the PCB to allow three gate delay time options, as shown in the table below. SL210 SL220 Closing Delay linked not linked <50ms*...
  • Page 55 T865 Initial Tuning & Adjustment B3.13 M860-00-Preliminary 3.11 Audio Processor 3.11.1 Line Amplifier Output Apply an on-channel signal from the RF generator at a level of -70dBm with 3kHz deviation (2.4kHz) [1.5kHz] at 1kHz. Adjust RV210 (front panel line level) to give an output of +10dBm on the 600 ohm line.
  • Page 56 B3.14 T865 Initial Tuning & Adjustment M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 57 T865 Functional Testing B4.1 M860-00-Preliminary T865 Functional Testing The following test procedures will confirm that the T865 has been tuned and adjusted correctly and is fully operational. Note 1: In this and following sections deviation settings are given first for wide bandwidth sets, followed by settings in brackets for mid bandwidth sets ( ) and narrow bandwidth sets [ ].
  • Page 58 B4.2 T865 Functional Testing M860-00-Preliminary 30/06/98 Copyright TEL...

  • Page 59: Current Consumption

    T865 Functional Testing B4.3 M860-00-Preliminary Current Consumption Connect the T865 to a 13.8V power supply. Rotate RV230 (front panel gating sensitivity) anticlockwise until the "Gate" LED is extinguished. Set switch SW201 (front panel monitor mute) to the position. Check that the current in the 13.8V power cable is less than 350mA. Rotate the RV230 clockwise until the "Gate"...

  • Page 60: Audio Distortion

    B4.4 T865 Functional Testing M860-00-Preliminary Audio Distortion The level of distortion measured at the line output (refer to Figure 1.3 in Part F) gives an indication of the accuracy of the IF alignment. Apply an accurate on-channel signal from the RF generator at a level of -70dBm with 3kHz deviation (2.4kHz) [1.5kHz] at 1kHz.

  • Page 61: De-Emphasised Audio Frequency Response

    T865 Functional Testing B4.5 M860-00-Preliminary De-emphasised Audio Frequency Response Set RV210 (front panel line level) to provide 0dBm output at 1kHz modulating fre- quency. Sweep the modulating frequency, checking that the line audio response closely follows that shown in Figure 4.1 - the limits should not be exceeded. Wide Bandwidth 25°C 13.8V Ref.

  • Page 62: Noise Mute (If Linked In)

    B4.6 T865 Functional Testing M860-00-Preliminary Noise Mute (If Linked In) Rotate RV230 (front panel gating sensitivity) fully anticlockwise. Apply an on-channel signal from the RF generator at a level of -110dBm with 3kHz deviation (2.4kHz) [1.5kHz] at 1kHz. Increase the RF level in 1dB steps, checking that the mute opens for an RF input level of approximately -105dBm.

  • Page 63: Carrier Level Mute (Carrier Mute Linked In)

    T865 Functional Testing B4.7 M860-00-Preliminary Carrier Level Mute (Carrier Mute Linked In) Apply an on-channel signal from the RF generator at a level of -120dBm with 3kHz deviation (2.4kHz) [1.5kHz] at 1kHz. Increase the RF level in 2dB steps and check that the mute opens at an RF level which corresponds with the preset level on RV235 (carrier mute), i.e.

  • Page 64: High Pass Filter

    B4.8 T865 Functional Testing M860-00-Preliminary 4.10.3 High Pass Filter Set the audio processor links as follows: Plug Link Function PL210 1 - 2 de-emphasised response PL230 2 - 3 audio from internal CTCSS speech filter PL240 4 - 5 audio input via PL230 or I/O pad Reset the RF signal generator output to -70dBm and note the line level (measure- ment A).
  • Page 65 If you still cannot trace the fault after progressing through them in a logical manner, contact your nearest Tait Dealer or Subsidiary. If necessary, you can get additional tech- nical help from the Customer Support Group, Radio Systems Division, Tait Electronics Ltd, Christchurch, New Zealand (full contact details are on page 2).
  • Page 66 B5.2 T865 Fault Finding M860-00-Preliminary Section Title Page Fault Finding Charts 5.7.1 Microcontroller 5.7.1.1 Basic Checks 5.7.1.2 Serial Communication 5.10 5.7.1.3 CTCSS Decode 5.11 5.7.2 Regulator 5.12 5.7.3 Synthesiser 5.13 5.7.4 Noise Mute 5.16 5.7.5 Carrier Mute 5.17 5.7.6 Receiver 5.18 5.7.7 Audio...

  • Page 67: Visual Checks

    T865 Fault Finding B5.3 M860-00-Preliminary Visual Checks Remove the covers from the T865 and inspect the PCB for damaged or broken compo- nents, paying particular attention to the surface mounted devices (SMDs). Check for defective solder joints. If repair or replacement of components is considered necessary, refer to Section 3 of Part A.

  • Page 68: Dc Checks

    B5.4 T865 Fault Finding M860-00-Preliminary DC Checks 5.4.1 Power Rails Refer to the test points & options diagrams in Section 6 for test point locations, and to the regulator fault finding chart (Section 5.7.2) for fault diagnosis. Check the 9V (TP602) and 13.8V (TP601) power supply test points in the regulator compartment with a DMM.

  • Page 69: Rf Checks

    T865 Fault Finding B5.5 M860-00-Preliminary RF Checks 5.5.1 VCO Frequency Check that the VCO is phase locked (refer to Section 5.4.2). Connect a frequency counter (level +19dBm) to the VCO input to the mixer (IC420). above Monitor the local oscillator frequency and check that it is 21.4MHz required receive frequency.

  • Page 70: Oscillator Stability

    B5.6 T865 Fault Finding M860-00-Preliminary Note: Poor sensitivity into the mixer can be caused by lack of drive level from the VCO (the drive level should be >+17dBm). Refer to the receiver fault finding charts (Section 5.7.6) for further information. 5.5.3 Oscillator Stability 5.5.3.1...

  • Page 71: If Distortion

    T865 Fault Finding B5.7 M860-00-Preliminary 5.5.5 IF Distortion If the audio distortion is still high after careful IF alignment (Section 3.7), sweep the IF to investigate the bandpass response. Apply an on channel RF signal modulated at 10Hz with approximately 12kHz (9kHz) [6kHz] deviation at an amplitude of -80dBm.

  • Page 72: Pgm800Win Generated Errors

    B5.8 T865 Fault Finding M860-00-Preliminary PGM800Win Generated Errors The following errors are those most likely to occur using PGM800Win. Refer to the PGM800Win software user ’s manual for a complete list of error messages. Channel Switch Set The programmed default channel was not accepted by the base station because a chan- nel is selected externally.

  • Page 73: Fault Finding Charts

    T865 Fault Finding B5.9 M860-00-Preliminary Fault Finding Charts Note: The standard test point designations used in this section are as follows: TP601 13.8V TP602 TP603 TP604 5.7.1 Microcontroller (IC810) 5.7.1.1 Basic Checks Is the 12.8MHz clock Check IC740 present on IC810 pin 21 (synthesiser).

  • Page 74: Serial Communication

    B5.10 T865 Fault Finding M860-00-Preliminary 5.7.1.2 Serial Communication Disconnect the Low/floating programming lead. Check the transistor Check pin state. Is IC810 pin 11 high? interface circuitry. (microcontroller) Noise on pin Check the SERIAL-COM and AUDIO-1/2 links. Connect the programming lead and use PGM800Win to read the rack/radio.

  • Page 75: Ctcss Decode

    T865 Fault Finding B5.11 M860-00-Preliminary 5.7.1.3 CTCSS Decode Use PGM800Win to Cannot select a channel select a channel Check serial communications. with a CTCSS tone (See separate flow chart). programmed. Set test equipment to correct No square wave or channel/CTCSS tone. uneven mark/space ratio Check the input filter Check IC830 pin 7.

  • Page 76: Regulator

    B5.12 T865 Fault Finding M860-00-Preliminary 5.7.2 Regulator Check for overheating components & short circuits. Check continuity 13.8V present on from D-range IC630 pin 3? connector pin 9. (D-range 1) 5.3V present on Replace IC630. IC630 pin 1? 9.0V present Check Q620, on TP202? Q630 &...

  • Page 77: Synthesiser

    T865 Fault Finding B5.13 M860-00-Preliminary 5.7.3 Synthesiser Refer to the synthesiser circuit diagram (sheet 7) in Section 6 and the VCO circuit dia- gram in Part E. No VCO RF output. VCO out of lock. 9V present at Check 9V reg. +5V present at Check 5V reg.
  • Page 78 B5.14 T865 Fault Finding M860-00-Preliminary Continued from previous page Replace synthesiser (IC740). Check phase detector output Check programming. pins (IC740 pins 3 & 4). Check serial bus Is reference Are there very narrow pulses when programming Programming and clock present (~50ns) at the reference frequency? i.e.
  • Page 79 T865 Fault Finding B5.15 M860-00-Preliminary Noisy synth; poor selectivity &/or poor residual FM. VCO phase locked? 3-14V present on Go to B. control line? Check inductors, Correct DC V biasing resistors present on Q1 VCO? & Q1. Loop filter & components around Replace if faulty.

  • Page 80: Noise Mute

    B5.16 T865 Fault Finding M860-00-Preliminary 5.7.4 Noise Mute Ensure PL250 is set for noise mute operation. Apply on channel signal *Modulated by 1kHz signal with @ -117dBm* to receiver. 3kHz (2.4kHz) [1.5kHz] deviation. Refer to Audio on receiver fault IC350 pin 7? finding chart.

  • Page 81: Carrier Mute

    T865 Fault Finding B5.17 M860-00-Preliminary 5.7.5 Carrier Mute Ensure PL250 is set for carrier mute operation, and the RSSI PCB is fitted. Apply on channel signal *Modulated by 1kHz signal with @ -95dBm* to receiver. 3kHz (2.4kHz) [1.5kHz] deviation. Refer to Audio on receiver fault IC350 pin 7?

  • Page 82: Receiver

    B5.18 T865 Fault Finding M860-00-Preliminary 5.7.6 Receiver Refer to the receiver IF and front end circuit diagrams (sheets 3 & 4) in Section 6. Poor sensitivity: worse than -117dBm. Ensure links SL405 to SL440 & link B are set correctly. (see Section 3.7) Ensure VCO, RF front end &...

  • Page 83: Audio

    T865 Fault Finding B5.19 M860-00-Preliminary 5.7.7 Audio Apply on channel signal *Modulated by 1kHz signal with @ -117dBm* to receiver. 3kHz (2.4kHz) [1.5kHz] deviation. Refer to Audio on receiver fault IC350 pin 7? finding chart. Audio on Check components IC210 pin 1? around IC210.
  • Page 84 B5.20 T865 Fault Finding M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 85 T865 PCB Information B6.1 M860-00-Preliminary T865 PCB Information This section provides the following information on the T865 receiver: • parts lists • grid reference index • PCB layouts • test points & options connections drawings • circuit diagrams Copyright TEL 30/06/98...
  • Page 86 B6.2 T865 PCB Information M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 87 T865 PCB Information B6.3 M860-00-Preliminary Introduction Product Type Identification You can identify the receiver type by checking the product code printed on a label on the rear of the chassis (product codes are explained in Section 1.3 in this Part of the manual, and Figure 1.1 in Part A shows typical labels).
  • Page 88 B6.4 T865 PCB Information M860-00-Preliminary Parts Lists The 10 digit numbers (000-00000-00) in this Parts List are “internal part numbers” (IPNs). We can process your spare parts orders more efficiently and accurately if you quote the IPN and provide a brief description of the part.
  • Page 89 T865 PCB Information B6.5 M860-00-Preliminary Grid Reference Index This section contains a component grid reference index to help you find components and labelled pads on the PCB layouts and circuit diagrams. This index lists the components and pads in alpha- numeric order, along with the appropriate alphanumeric grid references, as shown below: PCB layout reference...
  • Page 90 B6.6 T865 PCB Information M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 91 Item T865-10-0000 T865 Preliminary PCB Information Item T865-10-0000 Item X865-10-0000 Revision/Variant C Revision/Variant E Date created 25/05/98 Date created 25/05/98 No Ref ,349-00020-45, SCRW T/T M4X20MM P/POZ BZ #C403 ,015-21820-05, CAP CER0805 8P2+-0.1 200VGRM40 No Ref ,XE865VT10, T860 TUNABLE VCO ASSEMBLY #C405 ,015-21470-05, CAP CER0805 4P7+-0.1 200VGRM40...
  • Page 92 ,056-00021-09, IND FXD 820NH AX 4X9 C742B ,015-25100-08, CAP CER 0805 10N 10% X7R 50V L330 ,050-00016-58, COIL TAIT 658 2MH IF 7.5*7.5 C743 ,015-22470-01, CAP CER 0805 47P 5% NPO 50V L340 ,050-00016-58, COIL TAIT 658 2MH IF 7.5*7.5...
  • Page 93 Item X865-10-0000 T865 Preliminary PCB Information L450 ,056-00021-04, IND FXD 330NH AX R254 ,036-14820-10, RES M/F 0805 8K2 1% L460 ,050-00016-78, COIL RF 56UH NOM 3.5T AL CORE R255 ,036-15470-00, RES M/F 0805 47K 5% L470 ,050-00016-78, COIL RF 56UH NOM 3.5T AL CORE R256 ,036-14470-00, RES M/F 0805 4K7 5%...
  • Page 94 RES M/F 0805 68E 5% SW201 ,230-00010-30, SWITCH TOG SPDT R-ANG PCB MTG R785 ,036-14330-00, RES M/F 0805 3K3 5% T610 ,050-00016-50, COIL TAIT NO 650 455KHZ R786 ,036-12100-00, RES M/F 0805 10E 5% T86510 ,036-14220-00, RES M/F 0805 2K2 5% R787 ,036-12100-00,...
  • Page 95 Item T865-15-0000 T865 Preliminary PCB Information Item T865-15-0000 Item X865-15-0000 Revision/Variant C Revision/Variant E Date created 25/05/98 Date created 25/05/98 No Ref ,349-00020-45, SCRW T/T M4X20MM P/POZ BZ #C403 ,015-21820-05, CAP CER0805 8P2+-0.1 200VGRM40 No Ref ,XE865VT10, T860 TUNABLE VCO ASSEMBLY #C405 ,015-21470-05, CAP CER0805 4P7+-0.1 200VGRM40...
  • Page 96 ,056-00021-09, IND FXD 820NH AX 4X9 C759 ,015-25100-08, CAP CER 0805 10N 10% X7R 50V L330 ,050-00016-58, COIL TAIT 658 2MH IF 7.5*7.5 C761 ,015-25100-08, CAP CER 0805 10N 10% X7R 50V L340 ,050-00016-58, COIL TAIT 658 2MH IF 7.5*7.5...
  • Page 97 Item X865-15-0000 T865 Preliminary PCB Information L410 ,050-00016-78, COIL RF 56UH NOM 3.5T AL CORE R261 ,036-13150-00, RES M/F 0805 150E 5% L420 ,050-00016-78, COIL RF 56UH NOM 3.5T AL CORE R262 ,036-14100-10, RES M/F 0805 CHIP 1K 1% L430 ,052-08140-35, COIL A/W 3.5T/4.0MM HOR 0.8MM R263...
  • Page 98 RES M/F 0805 68E 5% SW201 ,230-00010-30, SWITCH TOG SPDT R-ANG PCB MTG R785 ,036-14330-00, RES M/F 0805 3K3 5% T610 ,050-00016-50, COIL TAIT NO 650 455KHZ R786 ,036-12100-00, RES M/F 0805 10E 5% T86520 ,036-14220-00, RES M/F 0805 2K2 5% R787 ,036-12100-00,...
  • Page 99 Item T865-20-0000 T865 Preliminary PCB Information Item T865-20-0000 Item X865-20-0000 Revision/Variant C Revision/Variant D Date created 25/05/98 Date created 25/05/98 No Ref ,349-00020-45, SCRW T/T M4X20MM P/POZ BZ %R223 ,036-12100-00, RES M/F 0805 10E 5% No Ref ,XE865VT20, T860 TUNABLE VCO ASSEMBLY &C203 ,015-25100-08, CAP CER 0805 10N 10% X7R 50V...
  • Page 100 ,056-00021-09, IND FXD 820NH AX 4X9 C759 ,015-25100-08, CAP CER 0805 10N 10% X7R 50V L330 ,050-00016-58, COIL TAIT 658 2MH IF 7.5*7.5 C761 ,015-25100-08, CAP CER 0805 10N 10% X7R 50V L340 ,050-00016-58, COIL TAIT 658 2MH IF 7.5*7.5...
  • Page 101 Item X865-20-0000 T865 Preliminary PCB Information L410 ,050-00016-78, COIL RF 56UH NOM 3.5T AL CORE R261 ,036-13150-00, RES M/F 0805 150E 5% L420 ,050-00016-78, COIL RF 56UH NOM 3.5T AL CORE R262 ,036-14100-10, RES M/F 0805 CHIP 1K 1% L430 ,052-08140-35, COIL A/W 3.5T/4.0MM HOR 0.8MM R263...
  • Page 102 RES M/F 0805 68E 5% SW201 ,230-00010-30, SWITCH TOG SPDT R-ANG PCB MTG R785 ,036-14330-00, RES M/F 0805 3K3 5% T610 ,050-00016-50, COIL TAIT NO 650 455KHZ R786 ,036-12100-00, RES M/F 0805 10E 5% T86520 ,036-14220-00, RES M/F 0805 2K2 5% R787 ,036-12100-00,...
  • Page 103 Item T865-25-0000 T865 Preliminary PCB Information Item T865-25-0000 Item X865-25-0000 Revision/Variant C Revision/Variant C Date created 25/05/98 Date created 25/05/98 No Ref ,349-00020-45, SCRW T/T M4X20MM P/POZ BZ %R223 ,036-12100-00, RES M/F 0805 10E 5% No Ref ,XE865VT20, T860 TUNABLE VCO ASSEMBLY &C203 ,015-24470-08, CAP CER 0805 4N7 10% X7R 50V...
  • Page 104 ,056-00021-09, IND FXD 820NH AX 4X9 C759 ,015-25100-08, CAP CER 0805 10N 10% X7R 50V L330 ,050-00016-58, COIL TAIT 658 2MH IF 7.5*7.5 C761 ,015-25100-08, CAP CER 0805 10N 10% X7R 50V L340 ,050-00016-58, COIL TAIT 658 2MH IF 7.5*7.5...
  • Page 105 Item X865-25-0000 T865 Preliminary PCB Information L410 ,050-00016-78, COIL RF 56UH NOM 3.5T AL CORE R261 ,036-13150-00, RES M/F 0805 150E 5% L420 ,050-00016-78, COIL RF 56UH NOM 3.5T AL CORE R262 ,036-14100-10, RES M/F 0805 CHIP 1K 1% L430 ,052-08140-35, COIL A/W 3.5T/4.0MM HOR 0.8MM R263...
  • Page 106 RES M/F 0805 68E 5% SW201 ,230-00010-30, SWITCH TOG SPDT R-ANG PCB MTG R785 ,036-14330-00, RES M/F 0805 3K3 5% T610 ,050-00016-50, COIL TAIT NO 650 455KHZ R786 ,036-12100-00, RES M/F 0805 10E 5% T86520 ,036-14220-00, RES M/F 0805 2K2 5% R787 ,036-12100-00,...
  • Page 107 T865 Grid Reference Index T865 Preliminary PCB Information Device Circuit Device Circuit Device Circuit Device Circuit T865 Grid Reference C340A 1:F4 3-A2 C640 1:M5 6-R5 C842 1:N2 8-L0 C340B 2:F4 3-B2 C651 1:M5 6-M4 C844 1:N3 8-L0 Index C344 2:F4 3-B0 C658 1:M5...
  • Page 108 T865 Preliminary PCB Information T865 Grid Reference Index Device Circuit Device Circuit Device Circuit Device Circuit IC640 1:M5 6-R5 P258 1:D3 2-P8 R207 2:C7 2-D8 R317 2:F6 3-L7 IC650 1:L5 6-E5 P260 1:D3 2-P7 &R209 2:C7 2-D8 R319 2:F6 3-L8 IC700 1:J3 7-A8...
  • Page 109 T865 Grid Reference Index T865 Preliminary PCB Information Device Circuit Device Circuit Device Circuit Device Circuit R625 1:N6 6-L7 R827 1:K4 8-L7 SK502 1:G6 5-D5 R629 1:M5 6-P6 R828 1:K4 8-L7 SK503 1:G6 5-D4 R633 1:M5 6-Q8 R829 1:K4 8-P9 SK504 1:G5 5-D3...
  • Page 110 T865 Preliminary PCB Information T865 Grid Reference Index Page B6.26...

  • Page 111: T867 Exciter

    M860-00-Preliminary Part C T867 Exciter This part of the manual is divided into six sections, as listed below. There is a detailed table of contents at the start of each section. Section Title General Information Circuit Operation Initial Tuning & Adjustment Functional Testing Fault Finding PCB Information...
  • Page 112 M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 113 T867 General Information C1.1 M860-00-Preliminary T867 General Information This section provides a brief description of the T867 exciter, along with detailed specifi- cations and a list of types available. The following topics are covered in this section. Section Title Page Introduction Specifications 1.2.1...
  • Page 114 C1.2 T867 General Information M860-00-Preliminary 30/06/98 Copyright TEL...

  • Page 115: Introduction

    The front panel controls include line sensitivity, microphone socket and carrier switch. This switch turns on the carrier (unmodulated) as an aid to servicing. The T867 is 60mm wide and occupies a single space in a Tait rack frame, which has the ability to accommodate up to seven standard modules.

  • Page 116: Specifications

    Line Keying Supply (if required) .. -50V DC Supply Current: Transmit .. 600mA Standby .. 150mA (typical) Operating Temperature Range .. -30°C to +60°C 1. Additional channels may be factory programmed. Contact your nearest Tait Dealer or Subsidiary. 30/06/98 Copyright TEL...

  • Page 117: Rf Section

    T867 General Information C1.5 M860-00-Preliminary Dimensions: Height .. 183mm Width .. 60mm Length .. 320mm Weight .. 2.1kg Time-Out Timer (optional) .. 0 to 5 minutes adjustable in 10 second steps Tail Timer .. 0 to 5 seconds adjustable in 100ms steps Transmit Key Time ..

  • Page 118: Audio Processor

    C1.6 T867 General Information M860-00-Preliminary Intermodulation .. -40dBc with interfering signal of -30dBc .. -70dBc with 25dB isolation & interfering signal of -30dBc (PA with output isolator) Radiated Spurious Emissions: Transmit .. -36dBm to 1GHz -30dBm to 4GHz Standby .. -57dBm to 1GHz -47dBm to 4GHz Power Output: ..

  • Page 119: Ctcss

    T867 General Information C1.7 M860-00-Preliminary Hum And Noise: Wide Bandwidth .. -55dB (300Hz to 3kHz [EIA]) typical Mid Bandwidth .. -53dB (CEPT) Narrow Bandwidth .. -50dB (CEPT) Compressor (optional): Attack Time .. 10ms Decay Time .. 800ms Range .. 50dB 1.2.4.3 CTCSS Standard Tones...

  • Page 120: Dti Cept Recommendation T

    C1.8 T867 General Information M860-00-Preliminary ETS 300 113 March 1996 Radio equipment and systems; land mobile service; technical characteristics and test conditions for radio equipment intended for the transmission of data (and speech) and having an antenna connector. ETS 300 219 October 1993 Radio equipment and systems;...

  • Page 121: Product Codes

    M860-00-Preliminary Product Codes The three groups of digits in the T860 Series II product code provide information about the model, type and options fitted, according to the conventions described below. The following explanation of T860 Series II product codes is not intended to suggest that any combination of features is necessarily available in any one product.

  • Page 122: T867 Standard Product Range

    T867 Standard Product Range The following table lists the range of standard T867 types (i.e. no options fitted) availa- ble at the time this manual was published. Consult your nearest Tait Dealer or Subsidi- ary for more information. Frequency Range (MHz)
  • Page 123 T867 Circuit Operation C2.1 M860-00-Preliminary T867 Circuit Operation This section provides a basic description of the circuit operation of the T867 exciter. Note: Unless otherwise specified, the term "PGM800Win" used in this and follow- ing sections refers to version 2.00 and later of the software. Refer to Section 6 where the parts lists, grid reference index and diagrams will provide detailed information on identifying and locating components and test points on the main PCB.
  • Page 124 C2.2 T867 Circuit Operation M860-00-Preliminary Figure Title Page T867 High Level Block Diagram T867 Microcontroller Block Diagram T867 Synthesiser Block Diagram T867 Two Point Modulation T867 Audio Processor Block Diagram T867 Power Supply & Regulators Block Diagram 2.10 T867 Transmit Timers 2.11 30/06/98 Copyright TEL...

  • Page 125: Introduction

    T867 Circuit Operation C2.3 M860-00-Preliminary Introduction The individual circuit blocks which make up the T867 are: • synthesiser • VCO • audio processor • drive amplifier • voltage regulators. Each of these circuit blocks is set in its own shielded compartment, formed as an inte- gral part of the main chassis.

  • Page 126: Microcontroller

    C2.4 T867 Circuit Operation M860-00-Preliminary Microcontroller (Refer to the microcontroller circuit diagram (sheet 8) in Section 6.2 or 6.3.) 5V Digital Watchdog Regulator Reset Reset Microcontroller Cavity Channel Select Port 12.8MHz Microcontroller Dual Digital Clock Auxiliary Potentiometer Output Port External Converter Serial Port...

  • Page 127: Synthesised Local Oscillator

    T867 Circuit Operation C2.5 M860-00-Preliminary Synthesised Local Oscillator (Refer to the synthesiser circuit diagram (sheet 7) in Section 6.2 or 6.3 and the VCO cir- cuit diagram in Part E.) FREQUENCY SYNTHESISER IC VCO PCB Modulation 12.8MHz Reference Fixed Reference Phase Charge Loop...

  • Page 128: Two Point Modulation

    C2.6 T867 Circuit Operation M860-00-Preliminary 2.3.1 Two Point Modulation Frequency modulation occurs by modulating both the VCO input and the synthesiser reference input. This process is called two point modulation and ensures a flat modula- tion response from 67Hz to 3kHz (2.55kHz for narrow bandwidth). The PLL has a fast response time, allowing a Tx key-up time of <30ms.

  • Page 129: Vco

    T867 Circuit Operation C2.7 M860-00-Preliminary (Refer to the VCO circuit diagram in Part E.) The VCO transistor (Q1) operates in a common source configuration, with an LC tank circuit coupled between its gate and drain to provide the feedback necessary for oscilla- tion.

  • Page 130: Audio Processor

    C2.8 T867 Circuit Operation M860-00-Preliminary Audio Processor (Refer to the audio processor circuit diagram (sheet 2) in Section 6.2 or 6.3.) Carrier Opto-coupler Opto-Key Tx Enable Constant Current Sink Tx Key Link Limiter Microphone Compressor PL215 Pre-amp. Link Output Microphone Inhibit mic.

  • Page 131: Keying Inputs

    T867 Circuit Operation C2.9 M860-00-Preliminary 2.5.3 Keying Inputs There are four ways to key the exciter: • pulling the Tx-Key line low (pin 13 on D-range 1 [PL100]) at the rear of the set); • pushing the "Carrier" button on the front panel - this will inhibit all audio; •...

  • Page 132: Power Supply & Regulator Circuits

    C2.10 T867 Circuit Operation M860-00-Preliminary Power Supply & Regulator Circuits (Refer to the regulators circuit diagram (sheet 6) in Section 6.2 or 6.3.) Buffer Micro- Power Tx Reg. Tx Enable controller Switch Watchdog µP 13.8V Nom. Timer From Rear D-Range 5V Dig Switching µP...

  • Page 133: Transmit Timers

    T867 Circuit Operation C2.11 M860-00-Preliminary Transmit Timers The transmit tail timer, transmit timeout timer and transmit lockout timer can all be set from PGM800Win. The fields for setting these are found on the system information page. These three timers operate as follows (refer also to Figure 2.7): Timer Function Adjustment...

  • Page 134: T867 Exciter Drive Amplifier

    C2.12 T867 Circuit Operation M860-00-Preliminary T867 Exciter Drive Amplifier (Refer to Figure 2.1 and the exciter circuit diagram (sheet 3) in Section 6.3.) A two-stage, wide band amplifier (Q365, Q370) provides an output level of approxi- mately 600mW (+27dBm) for an input of 100mW (+20dBm) from the VCO. IC330 pins 5, 6 &...
  • Page 135 T867 Initial Tuning & Adjustment C3.1 M860-00-Preliminary T867 Initial Tuning & Adjustment The following section describes both short and full tuning and adjustment procedures and provides information on: • channel programming • selecting required audio links • synthesiser alignment • modulator adjustment •...
  • Page 136 C3.2 T867 Initial Tuning & Adjustment M860-00-Preliminary Section Title Page Audio Processor 3.10 3.8.1 Two Point Modulation 3.10 3.8.2 Modulator Adjustment 3.10 3.8.3 Limiter Adjustment 3.11 3.8.4 Line Level Without Compressor 3.11 3.8.5 Compressor 3.11 3.8.5.1 Compressor On Line Input Only 3.11 3.8.5.2 Compressor On Microphone Input Only...

  • Page 137: Introduction

    PCB. Refer to Part C in the T800 Series Ancillary Equipment Service Manual (M800-00-101 or later issue) or consult your nearest Tait Dealer or Subsidiary for further details. 1. Use the "Read Module" function in PGM800Win to find out what the default channel is.

  • Page 138: Test Equipment Required

    C3.4 T867 Initial Tuning & Adjustment M860-00-Preliminary Test Equipment Required You will need the following test equipment: • computer with PGM800Win installed • T800 programming kit • module programming interface (e.g. T800-01-0004 - optional) • 13.8V power supply • digital multimeter •...

  • Page 139: Short Tuning Procedure

    T867 Initial Tuning & Adjustment C3.5 M860-00-Preliminary Short Tuning Procedure Use this procedure only if you want to reprogram the T867 to a frequency outside the 8MHz switching range and do not intend to carry out any other major adjustments or repairs.

  • Page 140: Two Point Modulation Adjustment

    C3.6 T867 Initial Tuning & Adjustment M860-00-Preliminary 3.4.3 Two Point Modulation Adjustment Note 1: In this and following sections deviation settings are given first for wide bandwidth sets, followed by settings in brackets for mid bandwidth sets ( ) and narrow bandwidth sets [ ]. Note 2: Reference modulation...

  • Page 141: Line-In Level Adjustment

    T867 Initial Tuning & Adjustment C3.7 M860-00-Preliminary Adjust RV210 (line sensitivity) fully clockwise and key the exciter by earthing the Tx Key line. Adjust “deviation” via PGM800Win to set the peak deviation to ±4.7kHz (±3.8kHz) [±2.3kHz] (you can use either the mouse or up and down arrow keys).

  • Page 142: Audio Processor Links

    C3.8 T867 Initial Tuning & Adjustment M860-00-Preliminary Audio Processor Links 3.5.1 Link Details Use the following table to set up the audio processor to the configuration you require. You should set the audio processor links before carrying out any of the tuning and adjustment procedures.
  • Page 143 T867 Initial Tuning & Adjustment C3.9 M860-00-Preliminary Synthesiser Alignment • Ensure that the T867 has been programmed with the required frequencies using PGM800Win software. • Single Channel Select a channel using PGM800Win. Multichannel Select the middle channel via PGM800Win. • Connect a high impedance voltmeter to PL4-1 or the junction of C35 and R30 in the VCO (this measures the synthesiser loop voltage).
  • Page 144 C3.10 T867 Initial Tuning & Adjustment M860-00-Preliminary Audio Processor 3.7.1 Two Point Modulation The T867 utilises two point modulation to obtain a wide audio bandwidth independent of the synthesiser loop filter response. This is achieved by simultaneously frequency modulating the VCO and phase modulating the synthesiser reference frequency. The relative signal levels fed to the two modulators are quite critical and cause interaction when setting up.
  • Page 145 T867 Initial Tuning & Adjustment C3.11 M860-00-Preliminary 3.7.3 Limiter Adjustment Note: If the T867 will be used over the whole 8MHz switching range, you must set the deviation for each channel. However, if the module will be used on fre- quencies that cover only a 1MHz (or less) switching range, you can set the deviation on the middle channel and use this value for all other channels with the “fill”...
  • Page 146 C3.12 T867 Initial Tuning & Adjustment M860-00-Preliminary Check that ±3kHz (±2.4kHz) [±1.5kHz] deviation is still available. Slowly increase the audio input level until the demodulated waveform shows sig- nificant signs of clipping (approximately ±4.5kHz (±3.6kHz) [±2.3kHz] deviation). Adjust RV220 anticlockwise until the demodulated waveform is just clipping (approximately ±4kHz (±3.2kHz) [±2kHz] deviation).
  • Page 147 T867 Functional Testing C4.1 M860-00-Preliminary T867 Functional Testing The following test procedures will confirm that the T867 has been tuned and adjusted correctly and is fully operational. Note 1: In this and following sections deviation settings are given first for wide bandwidth sets, followed by settings in brackets for mid bandwidth sets ( ) and narrow bandwidth sets [ ].
  • Page 148 C4.2 T867 Functional Testing M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 149 T867 Functional Testing C4.3 M860-00-Preliminary Current Consumption Connect the T867 to a 13.8V power supply. Connect an RF power meter to the T867 output socket. Check that the current in the 13.8V power cable is less than 150mA. Key the T867 by earthing the Tx-Key line (the carrier "On" LED should light). Check that the current is <600mA.
  • Page 150 C4.4 T867 Functional Testing M860-00-Preliminary Timer Function Adjustment Transmit Tail Sets the tail time during which the 0-5 seconds in 100ms transmitter stays keyed after the exter- steps nal key source has been removed. Transmit Timeout Sets the maximum continuous trans- 0-300 seconds in 10 mission time.
  • Page 151 T867 Functional Testing C4.5 M860-00-Preliminary Wide Bandwidth Peak + max. dev. = +1.0kHz @ 1000Hz Peak - max. dev. = -1.0kHz @ 1000Hz Frequency (Hz) Mid Bandwidth The mid bandwidth graph is the same shape as the wide bandwidth graph. The devia- tion figures are as follows: peak + max.
  • Page 152 C4.6 T867 Functional Testing M860-00-Preliminary Wide Bandwidth Peak + max. dev. = +4.9kHz @ 1500Hz Peak - max. dev. = -4.4kHz @ 2500Hz Above limiting (steady-state) Frequency (Hz) Mid Bandwidth The mid bandwidth graph is the same shape as the wide bandwidth graph. The devia- tion figures are as follows: peak + max.
  • Page 153 T867 Functional Testing C4.7 M860-00-Preliminary Audio Level Input Sensitivity • Adjust RV210 (line sensitivity) fully clockwise. • Check that the input sensitivities are better than those specified below: Line Input 600 ohms, ±3kHz (±2.4kHz) [±1.5kHz] deviation at 1kHz: with compressor -50dBm without compressor -30dBm...
  • Page 154 C4.8 T867 Functional Testing M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 155 If you still cannot trace the fault after progressing through them in a logical manner, contact your nearest Tait Dealer or Subsidiary. If necessary, you can get additional tech- nical help from the Customer Support Group, Radio Systems Division, Tait Electronics Ltd, Christchurch, New Zealand (full contact details are on page 2).
  • Page 156 C5.2 T867 Fault Finding M860-00-Preliminary Figure Title Page RF Diode Probe Circuit 30/06/98 Copyright TEL...

  • Page 157: Visual Checks

    T867 Fault Finding C5.3 M860-00-Preliminary Visual Checks Remove the covers from the T867 and inspect the PCB for damaged or broken compo- nents, paying particular attention to the surface mounted devices (SMD's). Check for defective solder joints. If repair or replacement is considered necessary, refer to Section 3 of Part A.

  • Page 158: Dc Checks

    C5.4 T867 Fault Finding M860-00-Preliminary DC Checks 5.4.1 Power Rails Refer to the test points and options diagrams in Section 6 for test point locations, and to the regulator fault finding chart (Section 5.7.2) for fault diagnosis. Check the 13.8V (TP601) and 9V (TP602) supplies at their test points in the regula- tor compartment with a DMM.

  • Page 159: Rf Checks

    T867 Fault Finding C5.5 M860-00-Preliminary RF Checks In-circuit RF levels may be measured with an RF probe on which the earth lead has been shortened to a minimum (i.e. 13mm). Refer to the circuit diagrams for typical levels. Figure 5.1 shows a suitable RF probe circuit.. Coax Probe DC to DVM or...

  • Page 160: Pgm800Win Generated Errors

    C5.6 T867 Fault Finding M860-00-Preliminary PGM800Win Generated Errors The following errors are those most likely to occur using PGM800Win. Refer to the PGM800Win software user ’s manual for a complete list of error messages. Channel Switch Set The programmed default channel change was not accepted by the base station because a channel is selected externally.

  • Page 161: Fault Finding Charts

    T867 Fault Finding C5.7 M860-00-Preliminary Fault Finding Charts Note: The standard test point designations used in this section are as follows: TP601 13.8V TP602 TP603 TP604 5.7.1 Microcontroller (IC810) 5.7.1.1 Basic Checks Is the 12.8MHz clock Check IC740 present on IC810 pin 21 (synthesiser).

  • Page 162: Serial Communication

    C5.8 T867 Fault Finding M860-00-Preliminary 5.7.1.2 Serial Communication Disconnect the Low/floating programming lead. Check the transistor Check pin state. Is IC810 pin 11 high? interface circuitry. (microcontroller) Noise on pin Check the SERIAL-COM and AUDIO-1/2 links. Connect the programming lead and use PGM800Win to read the rack/radio.

  • Page 163: Ctcss Encode

    T867 Fault Finding C5.9 M860-00-Preliminary 5.7.1.3 CTCSS Encode Use PGM800Win to Cannot select a channel select a channel Check serial communications. with a CTCSS tone (See separate flow chart). programmed. No square waves or Check IC810 pins 24, 25 uneven mark/space ratio &...

  • Page 164: Regulator

    C5.10 T867 Fault Finding M860-00-Preliminary 5.7.2 Regulator Check for overheating components & short circuits. Check continuity 13.8V present on from pin 9 of IC610 pin 3? D-range 1. 5.3V present on Replace IC610. IC610 pin 1? 9.0V present Check Q630, on TP602? Q620 &...

  • Page 165: Synthesiser

    T867 Fault Finding C5.11 M860-00-Preliminary 5.7.3 Synthesiser Refer to the synthesiser circuit diagram (sheet 7) in Section 6 and the VCO circuit dia- gram in Part E. No VCO RF output. VCO out of lock. 9V present at Check Tx reg., +5V present at Check 5V reg.
  • Page 166 C5.12 T867 Fault Finding M860-00-Preliminary Continued from previous page Check microcontroller Replace synthesiser section (IC810). (IC740). Check phase detector output Check programming. pins (IC740 pins 3 & 4). Check serial bus Is reference Are there very narrow pulses when programming Programming and clock present (~50ns) at the reference frequency?
  • Page 167 T867 Fault Finding C5.13 M860-00-Preliminary Noisy synth; poor residual FM. VCO phase locked? 3-14V present on Go to B. control line? Check inductors, Correct DC V biasing resistors present on Q1 VCO? & Q1. Loop filter & components around Replace if faulty. op.

  • Page 168: T867 Exciter Drive Amplifier

    C5.14 T867 Fault Finding M860-00-Preliminary 5.7.4 T867 Exciter Drive Amplifier Key exciter & lock synthesiser. 3.5V at Q365 collector? 10.5V at Q315 Check 10.5V at Q370 collector? collector? power rails. >5V present on Check IC330, IC330 pin 1? R324 & R326. Check Q310 &...
  • Page 169 T867 Fault Finding C5.15 M860-00-Preliminary 5.7.5 Audio Processor Key exciter & lock synthesiser. Connect 1kHz audio to external CTCSS input. Does exciter Audio output at Check audio path to modulate? IC260 pin 8? VCO control line. Check alignment Audio output at Check buffer IC260 of modulators.
  • Page 170 C5.16 T867 Fault Finding M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 171 T867 PCB Information C6.1 M860-00-Preliminary T867 PCB Information This section provides the following information on the T867 exciter: • parts lists • grid reference indexes • PCB layouts • test points & options connections drawings • circuit diagrams Copyright TEL 30/06/98...
  • Page 172 C6.2 T867 PCB Information M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 173 T867 PCB Information C6.3 M860-00-Preliminary Introduction Product Type Identification You can identify the exciter type by checking the product code printed on a label on the rear of the chassis (product codes are explained in Section 1.3 in this Part of the manual, and Figure 1.1 in Part A shows typical labels).
  • Page 174 C6.4 T867 PCB Information M860-00-Preliminary Parts Lists The 10 digit numbers (000-00000-00) in this Parts List are “internal part numbers” (IPNs). We can process your spare parts orders more efficiently and accurately if you quote the IPN and provide a brief description of the part.
  • Page 175 T867 PCB Information C6.5 M860-00-Preliminary Grid Reference Index This section contains a component grid reference index to help you find components and labelled pads on the PCB layouts and circuit diagrams. This index lists the components and pads in alpha- numeric order, along with the appropriate alphanumeric grid references, as shown below: PCB layout reference...
  • Page 176 C6.6 T867 PCB Information M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 177 Item T867-10-0000 T867 Preliminary PCB Information Item T867-10-0000 Item X867-10-0000 Revision/Variant C Revision/Variant D Date created 25/05/98 Date created 25/05/98 No Ref ,352-00010-29, NUT M4 NYLOC HEX #C269 ,015-21150-01, CAP CER 0805 1P5+-1/4P NPO 50V No Ref ,308-01007-01, HANDLE BASE STATION SERIES II #C294 ,015-22470-01, CAP CER 0805 47P 5% NPO 50V...
  • Page 178 T867 Preliminary PCB Information Item X867-10-0000 C370 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C910 ,015-02100-06, CAP CER 1210 10P NPO500VGRM42 C373 ,015-25470-08, CAP CER 0805 47N 10% X7R 50V C920 ,015-02180-06, CAP CER 1210 18P NPO500VGRM42 C376 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C930 ,015-02100-06,...
  • Page 179 Item X867-10-0000 T867 Preliminary PCB Information Q530 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R292 ,036-14470-00, RES M/F 0805 4K7 5% Q540 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R293 ,036-15470-00, RES M/F 0805 47K 5% Q550 ,000-10008-48, S) XSTR SMD BCW60 NPN SOT23 SS R294 ,036-14470-00,...
  • Page 180 RES M/F 0805 10K 5% SW230 ,232-00010-26, SWITCH PUSH SPDT R-ANG PCB MTG R734 ,036-13470-00, RES M/F 0805 470E 5% T610 ,050-00016-50, COIL TAIT NO 650 455KHZ R735 ,036-13470-00, RES M/F 0805 470E 5% T86710 ,036-15100-10, RES M/F 0805 10K 1% R736 ,036-13470-00,...
  • Page 181 Item T867-15-0000 T867 Preliminary PCB Information Item T867-15-0000 Item X867-15-0000 Revision/Variant C Revision/Variant C Date created 25/05/98 Date created 25/05/98 No Ref ,352-00010-29, NUT M4 NYLOC HEX #C269 ,015-21470-01, CAP CER 0805 4P7+-1/4P NPO 50V No Ref ,308-01007-01, HANDLE BASE STATION SERIES II #C294 ,015-22470-01, CAP CER 0805 47P 5% NPO 50V...
  • Page 182 T867 Preliminary PCB Information Item X867-15-0000 C370 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C910 ,015-02100-06, CAP CER 1210 10P NPO500VGRM42 C373 ,015-25470-08, CAP CER 0805 47N 10% X7R 50V C920 ,015-02180-06, CAP CER 1210 18P NPO500VGRM42 C376 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C930 ,015-02100-06,...
  • Page 183 Item X867-15-0000 T867 Preliminary PCB Information Q530 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R292 ,036-14470-00, RES M/F 0805 4K7 5% Q540 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R293 ,036-15470-00, RES M/F 0805 47K 5% Q550 ,000-10008-48, S) XSTR SMD BCW60 NPN SOT23 SS R294 ,036-14470-00,...
  • Page 184 RES M/F 0805 10K 5% SW230 ,232-00010-26, SWITCH PUSH SPDT R-ANG PCB MTG R734 ,036-13470-00, RES M/F 0805 470E 5% T610 ,050-00016-50, COIL TAIT NO 650 455KHZ R735 ,036-13470-00, RES M/F 0805 470E 5% T86715 ,036-15100-10, RES M/F 0805 10K 1% R736 ,036-13470-00,...
  • Page 185 Item T867-20-0000 T867 Preliminary PCB Information Item T867-20-0000 Item X867-20-0000 Revision/Variant C Revision/Variant D Date created 25/05/98 Date created 25/05/98 No Ref ,352-00010-29, NUT M4 NYLOC HEX #C269 ,015-21150-01, CAP CER 0805 1P5+-1/4P NPO 50V No Ref ,308-01007-01, HANDLE BASE STATION SERIES II #C294 ,015-22470-01, CAP CER 0805 47P 5% NPO 50V...
  • Page 186 T867 Preliminary PCB Information Item X867-20-0000 C370 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C910 ,015-02100-06, CAP CER 1210 10P NPO500VGRM42 C373 ,015-25470-08, CAP CER 0805 47N 10% X7R 50V C920 ,015-02180-06, CAP CER 1210 18P NPO500VGRM42 C376 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C930 ,015-02100-06,...
  • Page 187 Item X867-20-0000 T867 Preliminary PCB Information Q530 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R292 ,036-14470-00, RES M/F 0805 4K7 5% Q540 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R293 ,036-15470-00, RES M/F 0805 47K 5% Q550 ,000-10008-48, S) XSTR SMD BCW60 NPN SOT23 SS R294 ,036-14470-00,...
  • Page 188 RES M/F 0805 10K 5% SW230 ,232-00010-26, SWITCH PUSH SPDT R-ANG PCB MTG R734 ,036-13470-00, RES M/F 0805 470E 5% T610 ,050-00016-50, COIL TAIT NO 650 455KHZ R735 ,036-13470-00, RES M/F 0805 470E 5% T86720 ,036-15100-10, RES M/F 0805 10K 1% R736 ,036-13470-00,...
  • Page 189 Item T867-25-0000 T867 Preliminary PCB Information Item T867-25-0000 Item X867-25-0000 Revision/Variant C Revision/Variant C Date created 25/05/98 Date created 25/05/98 No Ref ,352-00010-29, NUT M4 NYLOC HEX #C269 ,015-21470-01, CAP CER 0805 4P7+-1/4P NPO 50V No Ref ,308-01007-01, HANDLE BASE STATION SERIES II #C294 ,015-22470-01, CAP CER 0805 47P 5% NPO 50V...
  • Page 190 T867 Preliminary PCB Information Item X867-25-0000 C370 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C910 ,015-02100-06, CAP CER 1210 10P NPO500VGRM42 C373 ,015-25470-08, CAP CER 0805 47N 10% X7R 50V C920 ,015-02180-06, CAP CER 1210 18P NPO500VGRM42 C376 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C930 ,015-02100-06,...
  • Page 191 Item X867-25-0000 T867 Preliminary PCB Information Q530 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R292 ,036-14470-00, RES M/F 0805 4K7 5% Q540 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R293 ,036-15470-00, RES M/F 0805 47K 5% Q550 ,000-10008-48, S) XSTR SMD BCW60 NPN SOT23 SS R294 ,036-14470-00,...
  • Page 192 RES M/F 0805 10K 5% SW230 ,232-00010-26, SWITCH PUSH SPDT R-ANG PCB MTG R734 ,036-13470-00, RES M/F 0805 470E 5% T610 ,050-00016-50, COIL TAIT NO 650 455KHZ R735 ,036-13470-00, RES M/F 0805 470E 5% T86725 ,036-15100-10, RES M/F 0805 10K 1% R736 ,036-13470-00,...
  • Page 193 Item T867-30-0000 T867 Preliminary PCB Information Item T867-30-0000 Item X867-30-0000 Revision/Variant C Revision/Variant C Date created 25/05/98 Date created 25/05/98 No Ref ,352-00010-29, NUT M4 NYLOC HEX #C269 ,015-21150-01, CAP CER 0805 1P5+-1/4P NPO 50V No Ref ,308-01007-01, HANDLE BASE STATION SERIES II #C294 ,015-22470-01, CAP CER 0805 47P 5% NPO 50V...
  • Page 194 T867 Preliminary PCB Information Item X867-30-0000 C370 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C910 ,015-02100-06, CAP CER 1210 10P NPO500VGRM42 C373 ,015-25470-08, CAP CER 0805 47N 10% X7R 50V C920 ,015-02180-06, CAP CER 1210 18P NPO500VGRM42 C376 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C930 ,015-02100-06,...
  • Page 195 Item X867-30-0000 T867 Preliminary PCB Information Q530 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R292 ,036-14470-00, RES M/F 0805 4K7 5% Q540 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R293 ,036-15470-00, RES M/F 0805 47K 5% Q550 ,000-10008-48, S) XSTR SMD BCW60 NPN SOT23 SS R294 ,036-14470-00,...
  • Page 196 RES M/F 0805 10K 5% SW230 ,232-00010-26, SWITCH PUSH SPDT R-ANG PCB MTG R734 ,036-13470-00, RES M/F 0805 470E 5% T610 ,050-00016-50, COIL TAIT NO 650 455KHZ R735 ,036-13470-00, RES M/F 0805 470E 5% T86730 ,036-15100-10, RES M/F 0805 10K 1% R736 ,036-13470-00,...
  • Page 197 Item T867-35-0000 T867 Preliminary PCB Information Item T867-35-0000 Item X867-35-0000 Revision/Variant C Revision/Variant B Date created 25/05/98 Date created 25/05/98 No Ref ,352-00010-29, NUT M4 NYLOC HEX #C269 ,015-21470-01, CAP CER 0805 4P7+-1/4P NPO 50V No Ref ,308-01007-01, HANDLE BASE STATION SERIES II #C294 ,015-22470-01, CAP CER 0805 47P 5% NPO 50V...
  • Page 198 T867 Preliminary PCB Information Item X867-35-0000 C370 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C910 ,015-02100-06, CAP CER 1210 10P NPO500VGRM42 C373 ,015-25470-08, CAP CER 0805 47N 10% X7R 50V C920 ,015-02180-06, CAP CER 1210 18P NPO500VGRM42 C376 ,015-24100-08, CAP CER 0805 1N 10% X7R 50V C930 ,015-02100-06,...
  • Page 199 Item X867-35-0000 T867 Preliminary PCB Information Q530 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R293 ,036-15470-00, RES M/F 0805 47K 5% Q540 ,000-10008-07, S) XSTR SMD BC807 PNP SOT23 AF R294 ,036-14470-00, RES M/F 0805 4K7 5% Q550 ,000-10008-48, S) XSTR SMD BCW60 NPN SOT23 SS R295 ,036-14270-00,...
  • Page 200 RES M/F 0805 10K 5% SW230 ,232-00010-26, SWITCH PUSH SPDT R-ANG PCB MTG R734 ,036-13470-00, RES M/F 0805 470E 5% T610 ,050-00016-50, COIL TAIT NO 650 455KHZ R735 ,036-13470-00, RES M/F 0805 470E 5% T86720 ,036-15100-10, RES M/F 0805 10K 1% R736 ,036-13470-00,...
  • Page 201 T867 Grid Reference Index T867 Preliminary PCB Information Device Circuit Device Circuit Device Circuit Device Circuit T867 Grid Reference C336 1:E8 3-D6 %C733 1:J3 7-M5 D730 1:H3 7-H1 C338 1:E8 3-F5 C735 1:J2 7-A1 D740 1:H3 7-K2 Index C340 1:E8 3-F5 C736 1:J2...
  • Page 202 T867 Preliminary PCB Information T867 Grid Reference Index Device Circuit Device Circuit Device Circuit Device Circuit 1-M0 Q660 1:L5 6-N1 #R265 1:C8 2-P3 R384 1:E5 3-L4 1-H8 Q670 1:L6 6-Q2 #R266 1:C8 2-P3 #R386 1:E6 3-M2 P100 1:P6 1-R8 Q710 1:J3 7-K8 R267...
  • Page 203 T867 Grid Reference Index T867 Preliminary PCB Information Device Circuit Device Circuit Device Circuit Device Circuit R742 1:H2 7-B4 R865 1:N4 8-E0 T83725 1:F2 10-D8 R743 1:H2 7-C5 R867 1:N3 8-E1 TOPFIDA 1:A3 10-H6 R744 1:G2 7-D4 R871 1:N3 8-G2 TOPFIDB 1:P8 10-H6 R746...
  • Page 204 T867 Preliminary PCB Information T867 Grid Reference Index Page C6.34...

  • Page 205: T869 Power Amplifiers

    Caution: There are no user serviceable components in this power amplifier. Refer all servicing to your nearest approved Tait Dealer or Service Cen- tre. This part of the manual is divided into five sections, as listed below. There is a detailed table of contents at the start of each section.
  • Page 206 M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 207 T869 General Information D1.1 M860-00-Preliminary T869 General Information This section provides a brief description of the T869 PA, along with detailed specifica- tions and a list of types available. The following topics are covered in this section. Section Title Page Introduction Specifications 1.2.1...
  • Page 208 D1.2 T869 General Information M860-00-Preliminary 30/06/98 Copyright TEL...

  • Page 209: Introduction

    Thermal sensors will also activate the fan automatically if the internal temperature reaches an unacceptable level. The T869 has a width of 120mm, occupying a double module in a Tait rack shelf which will accommodate up to seven standard modules to give an attractive and convenient installation.

  • Page 210: Specifications

    EIA specification. However, there are several parameters for which performance according to the CEPT specification is given. Details of test methods and the conditions which apply for Type Approval testing in all countries can be obtained from Tait Electronics Ltd. 1.2.2 General...
  • Page 211 T869 General Information D1.5 M860-00-Preliminary Spurious Emissions: Conducted - Transmit .. -36dBm to 1GHz -30dBm to 4GHz - Standby .. -57dBm to 1GHz -47dBm to 4GHz Radiated - Transmit .. -36dBm to 1GHz -30dBm to 4GHz - Standby .. -57dBm to 1GHz -47dBm to 4GHz Dimensions: Height...

  • Page 212: Product Codes

    M860-00-Preliminary Product Codes The three groups of digits in the T860 Series II product code provide information about the model, type and options fitted, according to the conventions described below. The following explanation of T860 Series II product codes is not intended to suggest that any combination of features is necessarily available in any one product.

  • Page 213: Standard Product Range

    Standard Product Range The following table lists the range of standard T865 types (i.e. no options fitted) availa- ble at the time this manual was published. Consult your nearest Tait Dealer or Subsidi- ary for more information. Frequency Range (MHz)
  • Page 214 D1.8 T869 General Information M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 215 T869 Circuit Operation D2.1 M860-00-Preliminary T869 Circuit Operation This section provides a basic description of the circuit operation of the T869 PA. The following topics are covered in this section. Section Title Page Introduction RF Circuitry Control Circuitry 2.3.1 Power Control 2.3.2 Driver Power Level 2.3.3...
  • Page 216 D2.2 T869 Circuit Operation M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 217 T869 Circuit Operation D2.3 M860-00-Preliminary Introduction Power Vsupply Control 300-500mW 110W 100W L500 L501 RF In RF Out #IC6 Directional Coupler Figure 2.1 T869 High Level Block Diagram The T869 comprises a two stage RF power amplifier with extensive control circuitry: •...
  • Page 218 D2.4 T869 Circuit Operation M860-00-Preliminary Figure 2.2 T869 Main Circuit Block Identification 30/06/98 Copyright TEL...
  • Page 219 T869 Circuit Operation D2.5 M860-00-Preliminary RF Circuitry (Refer to the RF section circuit diagram in Section 5.) The driver stage of the T869 consists of an RF power module which delivers 20-30W to the final transistors. This signal is split via a 3dB quadrature hybrid (L500) and used to drive two isolated push-pull stages (Q59, Q60, Q61, Q62).
  • Page 220 D2.6 T869 Circuit Operation M860-00-Preliminary Control Circuitry (Refer to the control section circuit diagram in Section 5.) Drive Level Clamp RV69 L1/L2 13.8V 13.8V Filtered Voltage Regulator Supply Supply LED Forward Power Meter Forward Power Alarm Low Forward Power LED RV43 RV48 Switch...
  • Page 221 T869 Circuit Operation D2.7 M860-00-Preliminary 2.3.1 Power Control The DC voltages from the directional coupler representing forward and reflected power are buffered by the two voltage followers, IC1 pins 1, 2 & 3 and pins 8, 9 & 10. Their out- puts are summed at an integrator (IC5 pins 1, 2 &...
  • Page 222 D2.8 T869 Circuit Operation M860-00-Preliminary 2.3.5 Forward And Reverse Power Metering Forward and reverse power signals from the two IC1 buffers are available for metering purposes. The output currents are adjustable via RV43 (forward power) and RV57 (reverse power). 2.3.6 Fan Control Circuitry Invert 13.8V...
  • Page 223 T869 Initial Adjustment D3.1 M860-00-Preliminary T869 Initial Adjustment The following section describes the full adjustment procedure to be carried out before operating the T869. Note: The T869 requires no RF tuning or alignment. Refer to Section 5 where the parts lists, grid reference index and diagrams will provide detailed information on identifying and locating components.
  • Page 224 D3.2 T869 Initial Adjustment M860-00-Preliminary 30/06/98 Copyright TEL...

  • Page 225: Test Equipment Required

    T869 Initial Adjustment D3.3 M860-00-Preliminary Test Equipment Required • DC power supply capable of delivering 30A at 13.8V. • Multimeter or DMM (e.g. Fluke 77). • RF power meter (e.g. HP 435 series or Bird Wattmeter). • 100W 30dB attenuator. •...

  • Page 226: Setting The Output Power

    D3.4 T869 Initial Adjustment M860-00-Preliminary Check that the regulated power control supply is approximately 7V. Note: The output power and alarm levels should be set with the cover shield on. If the cover is removed for other adjustment procedures, make a final check of the output power and alarm levels with the cover shield on.

  • Page 227: Limiting The Maximum Output Power

    T869 Initial Adjustment D3.5 M860-00-Preliminary Limiting The Maximum Output Power Refer to the control section circuit diagram in Section 5. remove LINK2 to bring Two chip resistors are provided on the PCB if R88 & R89 into circuit there is a requirement to set an absolute limit to the maximum output power.

  • Page 228: Setting Alarm Levels

    D3.6 T869 Initial Adjustment M860-00-Preliminary Setting Alarm Levels Note: If forward and reverse power metering is being used, set up their calibration (Section 3.6 and Section 3.7) before setting the alarm levels. 3.8.1 Forward Power Power up the T869 and adjust the front panel power control (RV63) so that the output power is at the alarm level required (e.g.
  • Page 229 If the fault still exists after having progressed through them in a logical manner, contact your nearest authorised Tait Dealer or Service Centre. Further assistance may be obtained from the Customer Support Group, Radio Systems Division, Tait Electronics Ltd, Christchurch, New Zealand.
  • Page 230 D4.2 T869 Fault Finding M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 231 T869 Fault Finding D4.3 M860-00-Preliminary Visual Checks Remove the cover from the T869 and inspect the PCB for damaged or broken com- ponents, paying particular attention to the surface mounted devices (SMD's). Check for defective solder joints. If repair or replacement is considered necessary, refer to Sections 3, 4, 5 and 6 of Part A.
  • Page 232 D4.4 T869 Fault Finding M860-00-Preliminary RF Checks The PA Fault Finding Chart (Section 4.5.1) provides a systematic approach for locating a fault in the RF circuitry. Use this chart in conjunction with Figure 4.1, which shows the locations of the 50Ω input and output test points for RF module #IC6 and RF transistors Q59-Q62.
  • Page 233 T869 Fault Finding D4.5 M860-00-Preliminary replace A4 pages D4.5/D4.6 with A3 pages D4.5/D4.6 Copyright TEL 30/06/98...
  • Page 234 D4.6 T869 Fault Finding M860-00-Preliminary replace A4 pages D4.5/D4.6 with A3 pages D4.5/D4.6 30/06/98 Copyright TEL...
  • Page 235 PA keyed? for short circuit or excessive wear. Replace parts as necessary. Is maximum power >100W over entire frequency range?* *Frequency Ranges T869-10: 220-244MHz Return PA to your local T869-20: 243-270MHz Tait service centre. T869-30: 265-285MHz Copyright TEL 30/06/98...
  • Page 236 D4.8 T869 Fault Finding M860-00-Preliminary 4.5.2 Power Control Approximate voltages (@ 260MHz) under normal operating conditions: Output Power Forward & Reverse Power Measurement 100W forward power at IC1 pin 1 — forward power at IC1 pin 2 — 3.2V reverse power at IC1 pin 8 0.5V —...
  • Page 237 T869 Fault Finding D4.9 M860-00-Preliminary 4.5.3 Fan Control Circuitry Key transmitter. Check Q10 & Q15 collector voltages. Check Q12 & Q13. Does fan run at Check IC3 pin 1 <1V. room temperature? Check Q9. Check Tx-key is low (at ground). Spray "freeze"...
  • Page 238 D4.10 T869 Fault Finding M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 239 T869 PCB Information D5.1.1 M860-00-Preliminary T869 PCB Information This section provides the following information on the T869 power amplifier: • parts lists • grid reference index • exploded view mechanical drawing • PCB layouts • circuit diagrams. Section Title Page Introduction 5.1.3 T869 Power Amplifier PCB...
  • Page 240 D5.1.2 T869 PCB Information M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 241 T869 PCB Information D5.1.3 M860-00-Preliminary Introduction PCB Identification All PCBs are identified by a unique 10 digit “internal part number” (IPN), e.g. 220-12345-00, which is screen printed onto the PCB (usually on the top side). The last 2 digits of this number define the issue status, which starts at 00 and increments through 01, 02, 03, etc.
  • Page 242 D5.1.4 T869 PCB Information M860-00-Preliminary Grid Reference Index To assist in locating components and labelled pads on the PCB layouts and circuit diagrams, a com- ponent grid reference index has been provided. This index lists the components and pads in alpha- numeric order, along with the appropriate alphanumeric grid references, as shown below: PCB layout reference...
  • Page 243 T869 PCB Information D5.2.1 M860-00-Preliminary T869 Power Amplifier PCB This section contains the following information. Section Page 220-01371-01 Parts List 5.2.3 Mechanical & Miscellaneous Parts 5.2.6 Mechanical Assembly 5.2.7 Rack Frame Guide Mechanical Assembly 5.2.8 Grid Reference Index 5.2.9 PCB Encoding Errors 5.2.11 PCB Layout - Bottom Side 5.2.13...
  • Page 244 D5.2.2 T869 PCB Information M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 245 T869 PCB Information D5.2.3 M860-00-Preliminary T869 Parts List (IPN 220-01371-01) How To Use This Parts List The components listed in this parts list are divided into two main types: those with a circuit reference (e.g. C2, D1, R121, etc.) and those without (miscellaneous and mechanical).
  • Page 246 D5.2.4 T869 PCB Information M860-00-Preliminary Description Description 015-24470-08 CAP CER 0805 CHIP 4N7 10% X7R 50V C151 015-06100-08 CAP CER 1206 CHIP 100N 10% X7R 50V 015-23680-08 CAP CER 0805 CHIP 680P 10% X7R 50V C152 014-07470-03 L) CAP TANT CHIP 4U7 25V +-20% 6X3.2X2.5MM 015-23680-08 CAP CER 0805 CHIP 680P 10% X7R 50V (SMD)
  • Page 247 T869 PCB Information D5.2.5 M860-00-Preliminary Description Description 065-10004-20 BEAD FE SMD CBD 4.6/3/3-4S2 RV48 042-04500-08 RES PRESET 5K CERMET 9.5MM SQ FLAT #L67 052-08130-45 COIL A/W 4.5T/3.0MM HOR 0.8MM WIRE 036-13680-00 RES M/F 0805 CHIP 680E 5% #L67 052-08130-45 COIL A/W 4.5T/3.0MM HOR 0.8MM WIRE RV52 042-04500-08 RES PRESET 5K CERMET 9.5MM SQ FLAT...
  • Page 248 D5.2.6 T869 PCB Information M860-00-Preliminary T869 Mechanical & Miscellaneous Parts (220-01371-01) Legend Description Legend Description 012-04100-05 CAP F/THRU 1N SUPPR FLTR STUD MTG 319-01190-01 SHIELD WALL HARMONIC FILTER T869PA 012-04150-01 CAP CER F/THRU 1N5 NO LEAD 319-01201-00 SHIELD LID HARMONIC FILTER T869PA 051-00006-02 SOLDER SPRING 1.3MM A4M1877 319-01202-00...
  • Page 249 T869 PCB Information D5.2.7 M860-00-Preliminary replace A4 pages D5.2.7/D5.2.8 with A3 pages D5.2.7/D5.2.8 Copyright TEL 30/06/98...
  • Page 250 D5.2.8 T869 PCB Information M860-00-Preliminary replace A4 pages D5.2.7/D5.2.8 with A3 pages D5.2.7/D5.2.8 30/06/98 Copyright TEL...
  • Page 251 T869 PCB Information D5.2.9 M860-00-Preliminary T869 Grid Reference Index (IPN 220-01371-01) How To Use This Grid Reference Index The first digit in the PCB layout reference is a "1" or "2", indicating the top or bottom side layout respectively, and the last two charac- ters give the location of the component on that diagram.
  • Page 252 D5.2.10 T869 PCB Information M860-00-Preliminary Device Circuit Device Circuit Device Circuit Device Circuit 1:H3 2-K9 R101 1:E4 1-J0 1:H4 2-K6 R102 1:D4 1-K0 1:H5 2-K3 R103 1:D4 1-L0 1:H6 2-K1 R104 1:D4 1-L0 1:P7 1-C6 R105 1:D4 1-M0 1:B5 1-E5 R106 1:D4 1-M0...
  • Page 253 T869 PCB Information D5.2.11 M860-00-Preliminary T869 PCB Encoding Errors (IPN 220-01371-01) The following diagram shows corrections to the encoding printed on the top side of the PCB. correction correction Copyright TEL 30/06/98...
  • Page 254 D5.2.12 T869 PCB Information M860-00-Preliminary 30/06/98 Copyright TEL...

  • Page 255: T860 Vco Pcb Information

    M860-00-Preliminary Part E T860 VCO PCB Information This part of the manual is divided into the sections listed below. These sections provide parts lists, PCB layouts and circuit diagrams for the T860 VCO PCB. There is a detailed table of contents at the start of each section.
  • Page 256 M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 257 T860 VCO PCB Information E1.1 M860-00-Preliminary T860 VCO PCB This section contains the following information. Section Page 220-01399-02 Parts List PCB Layout - Bottom Side PCB Layout - Top Side Circuit Diagram Copyright TEL 30/06/98...
  • Page 258 E1.2 T860 VCO PCB Information M860-00-Preliminary 30/06/98 Copyright TEL...
  • Page 259 T860 VCO PCB Information E1.3 M860-00-Preliminary T860 VCO Parts List (IPN 220-01399-02) How To Use This Parts List The components listed in this parts list are divided into two main types: those with a circuit reference (e.g. C2, D1, R121, etc.) and those without (miscellaneous and mechanical).
  • Page 260 E1.4 T860 VCO PCB Information M860-00-Preliminary Description Description 036-12220-00 RES M/F 0805 22E 5% 036-12560-00 RES M/F 0805 56E 5% 036-12220-00 RES M/F 0805 22E 5% 036-14270-00 RES M/F 0805 2K7 5% 036-13180-00 RES M/F 0805 180E 5% 036-14100-00 RES M/F 0805 1K 5% 036-12100-00 RES M/F 0805 10E 5% 036-14100-00...
  • Page 261 T860 VCO PCB Information E1.5 M860-00-Preliminary T860 VCO PCB (IPN 220-01399-02) - Bottom Side Copyright TEL 30/06/98...
  • Page 262 E1.6 T860 VCO PCB Information M860-00-Preliminary #CSB #C36 #CSA #CPA #CPB TBADMARK T860 VCO PCB (IPN 220-01399-02) - Top Side 30/06/98 Copyright TEL...
  • Page 263 M860-00-Preliminary Part F Installation This part of the manual is divided into the sections listed below. These sections give a brief description of the basic rack mounting and wiring procedures for the T865 receiver, T867 exciter and T869 power amplifier. Section Title Page...
  • Page 264 M860-00-Preliminary Figure Title Page T800-45-0001 PA Guide Kit T869 Chassis Connectors PA In Latched Position T869 D-Range Wiring - Rear View 30/06/98 Copyright TEL...

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