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Service Mode Adjustments
Items 23-24 GREY SCALE
(1) Receive the monochrome circular pattern.
(2) Set the brightness and colour to normal, contrast to
maximum.
(3) Enter to the service mode.
(4) Select No. 18 RBI (Red Bias), No, 19 GBI (Green Bias),
and No. 20 BBI (Blue Bias) and set each data to 0 with
+ or - key.
(5) Select No. 21 RD (Red Drive) and No. 22 BD (Blue
Drive) and set each data to 64 with + or - key.
(6) Turn Screen Control (T471) to minimum (fully counter-
clock-wise).
(7) Select the TV Service Menu No. 26.
(8) Advance Screen Control (T471) clockwise to obtain
just visible one color line. If line does not appear,
place this control to maximum (fully clockwise).
(9) Raise each Bias Level with 1, 2, 5, 6, 9 and 0 keys to
obtain just visible white line.
(10) Select the TV Service Menu No. 25 DRV (White
Balance Adjustments).
(11) Adjust Red and Blue Drive Levels alternately with 3, 4,
-/-- or RECALL key to produce normal black and white
picture in highlight areas.
(12) Check for proper grayscale at all brightness levels.
To turn off the TV Service Menu display, press the
MENU key.
Note: If Grayscale Adjustment is made after picture tube
replacement, check High Voltage
Protection Circuit
This TV set has a built-in power supply protection circuit.
It is provided to protect the TV set in case of a power supply circuit malfunctions. When something abnormality
occurs during TV reception, the TV set goes to the stand-by mode.
When an abnormality occurs during TV reception, it causes pin 24 of the CPU to go continually Low(less than
0.75V) for about one second. The CPU detects that this has occurred and outputs the signal from pin 15 to
switch off the power supply lines.
Releasing the protective circuit and restoring power supply
To release the protective circuit and restore power supply, turn the power to the TV set OFF and then ON again
via either the main power switch or the ON-OFF button on the remote control. This will work only if the power
supply trouble was temporary. If there is permanent trouble such as a damaged circuit, power cannot be
restored and the circuit will have to be repaired.
Red Bias +
Red Bias -
Green Bias -
Green Bias +
Blue Bias -
Blue Bias +
MENU
Press the
MENU
VSM
button to exit
from service
mode
ASM
-13-
TIMER
TV/AV
Red Drive -
1
2
3
4
Red Drive +
5
6
7
8
Blue Drive +
9
0
-/--
Blue Drive -
P
ZOOM
P
SWAP
CH SCAN
P
P
SURROUND
A•B
BBE
BASS
JXMLB
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