Troubleshooting Chart 1-8A, Control Head Model I - Motorola MCS 2000 Service Instructions Manual

9-14

Troubleshooting Chart 1-8A, Control Head Model I

Numbers in brackets refer to accompanying troubleshooting procedure overleaf.
START
Radio
No
can turn on/off? Check on/off switch (1.1)
(1.1)
Yes
5VDC
No
OK?
Check 5V supply (1.2)
(1.2)
Yes
Radio
No
resets control
head?
(2.1)
Yes
Reset
No
Check Q0652, U0657,
circuit works?
(2.2)
Yes
Under-
No
voltage detector
Replace U0657 (2.3)
works?
(2.3)
Yes
Micro-
No
Check Y0650 and U0653
processor clock
runs?
(3)
Yes
(Communication not OK)
Check the following:
BUS + (4.1)
Serial bus
No
communication BUS- (4.2)
OK? (4)
BUSY (4.3)
"FL 01/90"
BUS+/BUS- Comparator (4.4)
Radio never starts
Yes
after power on
stops only with accessory
December 6, 2004
Troubleshooting Troubleshooting Chart 1-8A, Control Head Model I
Error in radio!
D0674 (2.2)
(3)
Communication
Yes
on MIC Conn?
(4.5)
Accessory is defect!
No
Check the following:
SW B+ voltage in normal mode (5.1)
Multiplexer in normal position (5.2)
PTT input (5.3)
Monitor input (5.4)
SW B+ and
AUX input (5.5)
No
multiplexing of MIC
SW B+ in SB9600 Mode (5.6)
connector OK?
SW B+ in SB9600 Mode (high load) (5.7)
Multiplexer in SB9600 Position (5.8)
Yes
Volume
No
Check R0698 (6)
control OK?
(6)
Yes
Keypad
No
Check electrical connection to µP
OK?
Clean PCB or replace keypad (7)
(7)
Yes
Keypad backlight:
See LCD backlight (10)
LED
No Check U0653, Q0659, Q0660,
indicators
OK?
Yes
LCD
No
backlight
OK?
Yes
Yes
Check U0653, Q0651
and U0652 (10.1)
Check the following:
Text in
Defect outside segment area (11.1)
No
LCD display
Missing segments? (11.2)
OK?
Weak segments? (11.3)
LCD bias voltage (5 or 5.6 volts)? (12)
Yes
Check the following:
Secure
Check input from P0651 to µP U0653 (13.1)
No
keyloading
Check multiplexer position (13.2)
OK?
Check connections through multiplexer
including ESD protection diodes (13.3)
Yes
Micro-
No
Replace and factory programming
processor
and alignment necessary
OK?
Yes
END
Q0661 and LEDs (9)
No
All LEDs?
Check the LEDs
(10.2)
68P81083C20-D