SERVICE ADJUSTMENTS (Continued)
— 8 —
GRAYSCALE ADJUSTMENT
1. Set the picture controls to the Sports levels or Reset
(use MENU key and
▲
or
▼
key or RESET key).
2. Turn off the receiver and disconnect the AC power cord
(120V AC line).
3. While pressing the MENU key, reconnect the AC power
cord. The Service Menu display will now appear.
4. Select NO. 15 RB (Red Bias), NO. 16 GB (Green Bias),
and NO. 17 BB (Blue Bias) with
▲
or
▼
key and set each
data to 0 with + or – key.
5. Select NO. 18 RD (Red Drive) and NO. 20 BD (Blue Drive)
with
▲
or
▼
key and set each data to 64 with + or – key.
6. Set NO. 19 GD (Green Drive Reduction) data to 8, NO. 53
SB (Sub-Brightness) data to 32, NO. 54 SCO (Sub-Color)
data to 7, NO. 55 STI (Sub-Tint) to 19, and NO. 56 SSH
(Sub-Sharpness) data to 12 with
▲
or
▼
, and + or – keys.
7. Turn Screen Control (T402) to minimum (fully counter-
clockwise).
8. Select the Service Menu NO. 73 (Bias Adjustments) with
▲
or
▼
key.
9. Advance Screen Control (T402) clockwise to obtain just
visible one color line. If line does not appear, place this
control to maximum (fully clockwise).
10. Raise each Bias Level with 3, 6, and 9 keys to obtain just
visible white line. (See Figure 5.)
11. Select the Service Menu NO. 72 DRV (Drive Adjustments)
with
▲
or
▼
key.
12. Adjust Red and Blue Drive Levels alternately with 1, 3,
7, or 9 key to produce normal black and white picture in
highlight areas. (See Figure 6.)
13. Check for proper grayscale at all brightness levels.
To turn off the Service Menu display, press the MENU key.
Note: If Grayscale Adjustment is made after picture tube
replacement, check Brightness Level Adjustment.
FOCUS ADJUSTMENT
Adjust focus control (T402) for well defined scanning lines.
BRIGHTNESS LEVEL ADJUSTMENT
Note: Grayscale, RF AGC, Video Level, and High Voltage Check
must be adjusted before attempting Brightness Level
Adjustment.
1. Connect a color-bar generator to the antenna terminals.
2. Switch the generator to the crosshatch pattern.
3. Reset the picture controls to the Sports levels.
4. Connect voltmeter (high impedance) + lead to terminal
and – lead to terminal
voltmeter for 1.5V ~ 3V range.
5. Turn off the receiver and disconnect the AC power cord.
6. While pressing the MENU key, reconnect the AC power
cord. The Service Menu display will now appear.
7. Select NO. 53 SB (Sub Brightness) with
▲
or
▼
key.
8. Adjust the data with + or – key for 820mVDC.
9. Press the MENU key to turn off the Service Menu display.
10. Check brightness level on every active channel, readjust
(repeat steps 5 ~ 9), if necessary.
Note: Do not set to excessive brightness level, otherwise
the contrast level will be suppressed.
HIGH VOLTAGE HOLD-DOWN TEST
Every time the receiver is serviced, the HIGH VOLTAGE
HOLD-DOWN circuit must be tested for proper operation by
following these steps:
1. Connect receiver to 120V AC line. Tune receiver to active
channel. Reset the picture controls to the Sports levels.
2. Check that the voltage measured between TP7 and TE7
(ground side) is within 16.5 VDC to 21 VDC. If the voltage
is out of this range, the Hold-Down Circuit must be checked.
3. Connect a DC Voltage supply to
and
100 ohm 1/4W resistor. Adjust the DC voltage to 23 VDC.
The receiver should shutdown, losing raster and sound.
Then the receiver should turn off automatically. This
reaction indicates that the Hold-Down circuit is function-
ing properly. If the receiver does not shutdown, a
malfunction is indicated and its cause must be found and
corrected.
4. To obtain picture again, remove the DC Supply and wait
a few minutes. Now turn on the receiver.
HIGH VOLTAGE CHECK
Note: +B (+130V) Voltage Check and Grayscale Adjustment
must be completed before attempting High Voltage
Check.
1. Connect high voltage voltmeter – lead to ground, and
c lead to anode of picture tube.
2. Tune receiver to an active channel and confirm TV is
operating properly.
3. Eliminate the beam current by adjusting the contrast and
brightness controls to minimum.
4. Confirm high voltage is within 31.0 KV and 33.0 KV. If
reading is not within range, check horizontal circuit.
No high-voltage adjustment is provided on this chassis.
1
2
3
4
5
6
7
9
8
RB(–)
RB(+)
BB(–)
BB(+)
(N/A)
GB(–)
(N/A)
GB(+)
(N/A)
FOR RED BIAS ADJUSTMENT
FOR BLUE BIAS ADJUSTMENT
FOR GREEN BIAS ADJUSTMENT
Figure 5. Remote Control Number keys’ functions in
Service Menu NO. 73
1
2
3
4
5
6
7
9
8
RD(–)
RD(+)
BD(–)
BD(+)
(N/A)
(N/A)
(N/A)
(N/A)
(N/A)
Figure 6. Remote Control Number keys’ functions in
Service Menu NO. 72 DRV
FOR RED DRIVE ADJUSTMENT
FOR BLUE DRIVE ADJUSTMENT
