Safety Related Adjustment; Hv Hold-Down Adjustment - Sony KP-44PX3 Service Manual

When replacing the following components marked with
always check hold-down voltage and if necessary re-adjust.
Part Replaced (
Part Replaced (
D Board C8129, D8038, D8013, Q8024, R8002,
R8055, R8102, R8218, R8219, R8223
R8230, R5140, R9901, T5102, T5104,
T8005 (FBT)

5-1. HV Hold-Down Adjustment

1. Connect HV static voltmeter to HV Block.
2. Mount a resistor (R9901 : 43 k , 1/4 W, METAL
FILM) at CN8015.
3. Remove CN8006 and connect External Power Supply
to CN8006 1 pin (+135 V) and 2 pin (GND).
4. Turn on the set.
Power
Supply
SECTION 5 SAFETY RELATED ADJUSTMENT
)
R9901
)
+
1
CN8006
–
2
Fig. 5-1
Remove the cap off
from the unused
terminal and connect a
HV static voltmeter
there.
Fig. 5-2
below
D BOARD
CN8015
5. Receive the Dot signal and set PICTURE/
BRIGHTNESS to minimum.
6. Slowly up the supply voltage from 0 V to 135 V
until hold-down circuit works (picture disappears).
7. Read the HV static voltmeter peak HV voltage.
Spec : 33.7 ~ 35.3 kV
8. If Hold-down voltage is less than 33.7 kV then
replace R9901 43 k with that of 39 k , and
check if the voltage is within the spec.
9. If hold-down voltage is greater than 35.3 kV then
replace R9901 of 43 k with that of 47 k , and
check if the voltage is within the spec.
– 23 –
– CONDUCTOR SIDE –
CN8006
Fig. 5-3
CN8015
R9901
Fig. 5-4
KP-44PX3
RM-945