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When the Main DC voltage will decrease w.r.t. the reference
voltage V
, the 'SUP_ENABLE' line will be activated via
BAT
TS7505, TS7508 and R3559. This will switch 'off' the Main
supply via TS7529.
Switch to 'On' (via 'SUP-ENABLE')
Via the 'STANDBY' command from the OTC, the MOSFETS
7141 and 7131 (diagram A2) are switched 'on.' When the OTC
senses the +5V and +8V, a command is given to the HOP to
start the drive (via I
When this is sensed via the 'SUP-ENABLE' line (at the base of
line transistor TS7421, diagram A3), the main supply is
switched 'on' via TS7529 (diagram A1.)
Protection
When, for any reason (interruptions or defective components),
the feedback loop of the Main supply will fail, the V
This is detected via zener diodes D6507, D6508, and D6513.
This will 'ignite' thyristor T7503, which will result in the blowing
of fuse 1503.
Audio Supply
The pulses on the secondary winding of L5506 (or L5512) are
rectified by D6535 (+16 V) and D6536 (-16V), and smoothed by
C2542 and C2543.
9.4
Control (Diagram B5)
A0...A19
FLASH
FLASH
DRAM
(SW)
EPG
(TXT)
CVBS-TXT
H, V
+3V3
+5V2
+3V3 +
RESET
+3V3
KEYBOARD
+5V
+8V
TUNER
WIRELESS EXPANDER
WIRELESS TRANSMITTER
3D COMBFILTER
DVD INTERFACE EXPANDER
DVD ENGINE
MOIRÉ EXPANDER
AUTOSCAVEM DAC
PIP I/O EXPANDER
BOCMA PIP
SfH I/O EXPANDER
Vchip PIP
Figure 9-9 Microprocessor (OTC)
9.4.1
OTC
Introduction
The SAA5801 (IC7001) is called the OTC (OSD, TXT/CC, and
Control.) In this IC, the microprocessor and the CC-decoder
are integrated.
Some of its functions are:
•
Set control.
•
CC/OSD acquisition.
•
RGB-outputs to the HOP
•
Menu blending; for blending the contrast, software
controlled.
•
I/O-ports for I
Circuit Descriptions and Abbreviation List
2
C.)
D0...D15
7001
P50-OUT
120
NVM
SAM
(PROG)
119
+3V3
SEL_IN_2
117
4005
SAA5801
DEGAUSSING
115
LIGHT SENSOR
5
110
STATUS SC3
109
FRONT DETECT
83,84
108
STANDBY
RESET
74
104
SEL_IN_1
103
RC5/RC6
ON/OFF-LED
100
113
POR
99
P50-IN
97
SDM
107
96
SOUND ENABLE
106
95
RESET AUDIO
4006
105
94
I 2 C1
slow
FRAME
85/86
81
RGB, BLENDING
77,78,79,80
I 2 C2
fast
87/88
I 2 C3
91/92
2
C, RC5/RC6, LED, and service modes.
•
Data Storage
•
•
•
Power Supply
All ICs in this part are supplied with 3V3. For this voltage, a 3V3
stabilizer is used (IC7005.)
With the circuitry around TS7003 and 7004 (diagram B5), a
reset is generated to wake up the OTC (pin 74.) During this
reset, all I/O pins of the OTC are made 'high.'
will rise.
BAT
Via pins 105 and 106, the +8 V and the +5 V are sensed. If one
of them is not present, the Main supply is switched 'off' (set
goes into protection mode, and the red LED blinks at 3 Hz.)
The OTC will generate an error code to indicate the problem.
OSD/CC
The horizontal (H
fed to the OTC for stable OSD and CC.
The RGB-outputs (77/78/79) together with fading (pin 80) are
fed to the HOP. The fading pin has a double function: it is used
for making a transparent menu and as a fast-blanking signal for
CC.
2
9.4.2
I
C Bus
There are three I
•
•
•
9.4.3
NVM
The Non Volatile Memory contains all set related data that must
be kept permanently, such as:
•
•
•
•
•
•
HIP
HOP
MSP
9.5
Tuner & IF (Diagram A8 and B2)
FBX
TOPIC
NVM
The tuner/splitter is I
CL 26532041_063.eps
off-air and cable channels.
110402
The tuning is done via I
V. This voltage (V
standby supply, via D6110 and R3116//R3115 and a 33 V
zener diode (D6200.) The OTC, together with the HIP, controls
the tuning procedure. There is also automatic switching for the
different video systems.
The IF-filter is integrated in a SAW (Surface Acoustic Wave)
filter. The type of this filter depends on the received
standard(s.) There are two SAW filters: one for filtering picture-
IF and a second one for sound-IF.
The output of the tuner is controlled via an IF-amplifier with
AGC-control. This is a voltage feedback from pin 62 of the HIP
to pin 1 of the tuner. AGC take-over point is adjusted via the
service alignment mode 'Tuner AGC.' If there is too much noise
EM5A NTSC
Error code generation.
The software is 2 MB (Megabytes), and is stored in IC7006.
IC7007 is a DRAM of 4 Mbit and this IC is used to store
data of a working set.
The Non Volatile Memory IC7011 is a 4 kB version
M24C32W6.
) and vertical (V
D
SYNC
2
C busses used:
Slow (max. 100 kHz) hardware I
for the Tuner.
Fast (max. 400 kHz) hardware I
for all ICs.
2
Separate short bus, called I
C3, for the Non Volatile
Memory (NVM), to avoid data corruption.
Software identification.
Operational hours.
Error-codes.
Option codes.
All factory alignments.
Last Status items for the customer + a complete factory
recall.
2
C controlled, and is capable of receiving
2
C. The reference voltage on pin 9 is 33
) is derived from the secondary side of the
TUN
9.
EN 123
) sync pulses are also
2
2
C-bus, called I
C1, used
2
2
C -bus, called I
C2, used
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