CM151
3-3
CA - SERVICING
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 on pins 9, 23, 46, and 48
Serial Data, Serial Clock at pins 27, 28
HORIZONTAL CIRCUIT
Check the following:
Horizontal drive to base of QX3203 predriver
Driver transformer output at base of Q3203
Shutdown voltage at cathode of ZDX3004
Scan-derived vo25, +35 and +200 volts
MICROPROCESSOR IC6000
Check the following:
IR inout on pin 2
+5 volts on pin 27
Clock Xtal on pins 24, and 25
Serial Data, Serial Clock on pins 36 and 38
Reset at pin 30
Horiz. Flyback on pin 1, Vert pulse on pin 2
R, G, B out on pins 50, 51, and 52
VERTICAL CIRCUIT IC2100
Check the following:
Vertical drive pulse at pin 3
+25 volts at pins 2,10 and 11
Vertical out at pin 1
Poor Linearity: Check C2102 and C2103
SERVICE ADJUSTMENTS
(Electrical)
G2 ADJUST
1 . Set brightness and contrast in the Video menu to
mid range.
2. Set color level to minimum .
3. Connect the output of an NTSC generator to the
antenna input on the receiver.
4. Select a color bar signal and turn color off .
Adjust the G2 control so that the bar patterns
range from completely black to a ‘not overdriven ‘
(Not saturated) white. There should be a distinct
difference between the black and white bars . Also
the different shades of gray should also be
distinguishable if the G2 is set correctly .
5. Return color level control to its normal setting.
Leave generator connected if the RGB cutoff is to
be adjusted.
VERTICAL SIZE
1. Vertical size adjustment is found in the Factory
Menu (item 12).
SERVICE ADJUSTMENTS
2. Horizontal size is on the 32” and 36” models.
Adjustment is found in the factory Menu (Item
13).
FOCUS ADJUSTMENT
Connect a color bar pattern to the receiver and adjust
the user controls for a good picture . Push the button
to the Video Menu, then proceed to adjust the Focus
control until distortion of the letters in the menu
disappears.
SERVICE ADJUSTMENTS (Service Menu)
CA ADJUSTMENTS OF RGB CUTOFFS
1
.
If the main module or CRT has been replaced, select
“Cool” in the user video menu under Color Temp. The
sets items G Gain 1 (Green gain cool) and B Gain
1
(Blue gain cool), in the Service menu to the default
setting for correct screen size as listed in the Service
Menu (See table ). Set color level and contrast to
minimum, and Tint to mid range.
2. Enter the Service menu to gain access to the cutoff
adjustments. (Factory mode item 00 must be set to
1 to gain access to these adjustment).
3. Connected the output of an NTSC generator to the
antenna input of the receiver, set the generator to a
Pure white signal, chroma off. Adjust the color and
contrast to obtain a grey raster picture.
4. Carefully observe which color is predominant on the
CRT (Red, green, or blue). Do not adjust the cut off
control of this color (Leave it zero). Adjust the other
two cut off controls for a smog grey color on the
display.
6. Set the generator to a color bar pattern and turn
the chroma Off. Check that set displays gray scale
from black to white. If black level is too high,
readjust RF Brightness (Item 9).
7. Return the color level control to preset.
8. Select Warm in the user video menu under Color
Temp. Then adjust items R Cut (22), G Cut (23), B
Cut (24), G Gain 2 (25) and B Gain 2 (26) accord-
ing to the Installer’s Menu tables. Readjust each
value adding the respective number by looking in
the corresponding screen size column.
9. Disable the Factory Menu and select “cool” in the
user Video Menu under Color Temp. Factory Mode
(Item 00) must be set to zero.
