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SERVICING
POWER SUPPLY
Stand by Voltages
+150 DC at RX3404
+ 130 DC at CX3420
+ 15 DC at emitter of Q3404
+5V DC at pin 3 of IC3442
Power On
Keyboard input at IC6000 pin 19 and 20
IR input at IC6000 pin 2
Power On output at IC6000 pin 52
Q3402 power supply switching transistor
Switched
Voltages
+9 volts DC at pin 3 of IC3441
+15 volts DC at collector of Q3404
Sweep Derived Voltages
+23 volts DC at the junction of CX3268 and RX3242
+35 volts DC at CX327
+-245 volts DC at junction of CX3296 and RX3217
CRT Filament at pins 1 and 2 connector 2F5
VIDEO PROCESSOR
ICX2200
Key operating
Signals
Composite Video out to pin 41
Composite Audio out at pin 2
Horizontal Drive at pin 32
Vertical Drive at pin 24
Video output Blue at 2C5 pin 3
Video output Green at 2C5 pin 2
Video output Red at 2C5 pin 1
B+ 9 volts -pins 9,23,33,46
and 48
Serial Data, Serial Clock pins 30, 3 1
r
VERTICAL
CIRCUIT
Vertical drive pulse pin 3
+23 volts pins 2,10, and 11
Vertical out pin 1
Poor Linearity check C2114, C2115
HORIZONTAL
CIRCUIT
Horizontal drive to base of Q3202 predriver
Driver transformer output base of Q3208
Shutdown voltage cathode D225 1
Scan derived voltages +23, +35 and +245 volts
MICROPROCESSOR
IC6000
IR in on pin 2
Power Ctl pin 52
+5 volts pins 22, 39
Clock Xtal pins 36, 37
Reset pin 35
H Sync pin 28, V Sync pin 29
R, G, B out pins 24,25,26
SERVICE ADJUSTMENTS
(Mechanical)
1. Vertical Size-R2133 Adjust R2133 for about l/2"
overscan at top and bottom of picture.
2. Horizontal Width (Some Models) Adjust R3249 for
l/2" overscan on both sides of the picture.
Use the following
procedure
when re-setting
G-2:
1.
2.
3.
4.
5.
Set brightness and contrast in the Video Menu to
mid-range.
Set color level to minimum, and tint to midrange.
Connect output of an NTSC generator to antenna input
on receiver.
Select a color bar signal and turn color off. Adjust G2
control so that bar patterns range from completely black
to a "not overdriven" (not saturated) white. There
should be a distinct difference between black and white
bars. Different shades of gray should be distinguish-
able if the G2 is set correctly.
Return the color level control to its normal setting.
Leave generator connected if RGB cutoff is to be
adjusted.
G2 ADJUST
ADJUSTMENT
OF RGB CUTOFF
G2 control
must be adjusted
before
RGB drive.
1. If main module or CRT has been replaced, select
default settings for drive and cutoff for RGB as listed in
Service Menu.
2.
3.
Set color level to minimum and tint to mid range.
Connect output of an NTSC generator to antenna input
of receiver. Set generator to a white raster signals,
chroma off.
4.
5.
Enter Service Menu to gain access to cutoff
adjustments. (Factory Mode item 00 must be set to 1 to
gain access to these adjustments).
Set items 24 R Cut, 25 G Cut, and 26 B Cut to 0. Set B
and G DRV to the recommended settings (page 4 items
27 and 28).
6.
7.
8.
Carefully observe which color is predominant on CRT.
Do not adjust cutoff predominant color from 0 setting.
Adjust other two cutoff controls for best white screen
display.
Set generator to a color bar pattern and turn chroma off.
Check that set displays a good gray scale from black to
white. If black level is too high, readjust G2 slightly.
Return the color level control to normal.
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