Zenith A19A02D, Руководство по обслуживанию

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CM150
3-4
GA - SERVICING
SERVICING (continued)
volt P-P at emitter of Q9706.
2. Audio Balance (19"/20" Models) Adjusts R9745 for
equal output at collectors of Q9701 and Q9703.
3. HORIZONTAL WIDTH (25"/27" Models) Adjusts R3249
for 1/2" overscan on both sides of the picture.
FOCUS ADJUSTMENT
Connect a color bar pattern to the receiver and adjust
the user controls for a good picture. Adjust the Focus
control, then push the menu button to video menu then
proceed until there is no distortion in the letters of the
menu.
GA1/GA2 RGB CUTOFF (1164 Micro)
The G2 control must be adjusted before RGB drive.
1. If the main module or CRT has been replaced, set
items #23 G GAIN and #24 B GAIN, in the Service
Menu, to the default setting for the correct screen
size as listed in the Service Menu (see above table).
2. Set color level to minimum and Tint to midrange.
3. Connect the output of an NTSC generator to the
antenna input of the receiver. Set the generator to
a pure white signal, chroma off.
4. Access the Service menu to gain access to the cut-
off adjustments, (Factory mode item 00 must be set
to 1 to gain access to these adjustments).
5. Set items 22 R Cut, 23 G Cut and 24 B. Cut to the
values shown in the above table.
6. Carefully observe which color is predominant on the
CRT - DO NOT adjust the cutoff control for this color.
Adjust the other two cutoff controls for the best
white screen display.
7. Set the generator to a color bar patter and turn the
chroma off. Check that the set displays a good gray
scale from black to white. If black level is too high
readjust the item #9 RF Brightness.
8. Return the color level control to normal.
GA3 OF RGB CUTOFF (1305 Micro)
The G2 control must be adjusted before RGB drive.
1. If the main module or CRT has been replaced, select
“Cool” in the user video menu under Color Temp.
Then set items #25 Gain 1 (Green gain cool) and
#26 B Gain 1 (Blue gain cool), in the Service Menu
to the default setting for the correct screen size as
listed in the Service Menu (see table above). Set
Color level to minimum and Tint to mid range.
2. Connect the output of an NTSC generator to the
antenna input of the receiver. Set the generator to
the Pure white signal, chroma off.
3. Access the Service Menu to gain access to the cut-
off adjustments, (Factory mode item 00 must be set
to 1 to gain access to these adjustments).
4. Set items 22 R Cut, 23 G Cut, 24 B cut to the values
shown in the table.
5. Carefully observe which color is predominant on the
CRT. DO NOT adjust the cutoff control of this color.
Adjust the other two cutoff controls for the best
white screen display.
6. Set the generator to a color bar pattern and turn
SERVICE ADJUSTMENTS
GA1 GA2
Tube Size 19” 20” 25” 27”
Customer Contrast 0 0 0 0
RF Bright/Aux Bright 36 36 26 28
Customer Brightness 31 31 31 31
Red Cutoff 0 0 10 5
Green Cutoff 0 0 10 5
Blue Cutoff 0 0 10 5
Green Gain 90 90 90 90
Blue Gain 90 90 90 90
GA3
Tube Size 25” 27”
Customer Contrast 0 0
RF Bright/Aux Bright 40 40
Customer Brightness 32 32
Color Temp Cool Cool
Red Cut 1 15 15
Green Cut 1 8 5
Blue Cut 1 12 12
Green Gain 1 95 100
Blue Gain 1 70 80
Color Temp Warm Warm
Red Cut 2 15 16
Green Cut 2 10 8
Blue Cut 2 17 16
Green Gain 2 70 75
Blue Gain 2 25 32