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10
Other adjustments
Adjustment
Red reference
Green reference
Blue reference
Red gain
Green gain
Blue gain
Peak white limit
Luma delay
Service adjustments
O
Power supply block
Supply voltage and protection circuit
1. Set brightness and contrast to normal level. Connect a
universal voltmeter to the cathode of Do11.
2. Adjust the U1 voltage with Ro45. The voltage depends
on the picture tube type, refer to the section "Variable
components".
3. Check the over-current protection after making any
service operations in the primary circuit of the power
supply. Activate the service mode and then switch the
set to stand-by mode. Short circuit the cathode of
Do13 to the ground and keep the short circuit
connected. When the over-current protection works
correctly, the power supply will try to start 2-3 times
before it stops permanently. Remove the short circuit
and switch on the receiver by pressing the mains
button.
SR Tuner/IF module (Frontend)
Tuner AGC
The tuner AGC is adjusted with a potentiometer through
a hole in the heat sink (see picture below).
Apply a 1 mV (60 dBµV) test signal and adjust the picture
just without noise.
Code OSD name
18
R REF.
19
G REF.
20
B REF.
15
R GAIN
16
G GAIN
17
B GAIN
21
PWL
14
LUMA DELAY
81403760
AGC
Note!
This procedure is necessary e.g. when the picture tube, CRT-
module etc. has been replaced.
Apply a test picture and adjust the R, G and B references.
Then adjust the R, G and B gains.
Normally no need to adjust.
Separate adjustment for Video, PAL BG, PAL DK/I and Secam L.
K
Horizontal deflection block
Horizontal linearity
Adjust with Lk2.
Focusing
Set brightness and contrast to normal level. Use
crosshatch pattern and adjust the picture for optimum
resolution.
(Screen grid voltage) Ug2 voltage
1. Set brightness and colour saturation to normal level
and contrast to minimum.
2. At the end of the vertical blanking, there is a black
current measurement pulse (clamp pulse) at pin 9 of
ICh1, ICh2 and ICh3. Use an oscilloscope and find the
output stage with the highest cut-off (i.e. the highest
voltage during the black current measurement pulse).
3. Adjust the voltage of the clamp pulse to +140 V with
Ug2 (see figure).
clamp pulse
0 V
Note! Adjust the voltage with a clamp pulse.
140 V
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