Safety Related Adjustment; Hv Hold-Down Adjustment - Sony KP-44PX2 Service Manual

When replacing the following components marked with
schematic diagram, always check hold-down voltage and if necessary
re-adjust.
Part Replaced (
Part Replaced (
D Board C5123, C5127, C5130, C5143, D5115,
D5204, Q5104, R5136, R5138, R5140,
R9901, T5102, T5104, T5103 (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 CN5003.
3. Remove CN5002 and connect External Power Supply
to CN5002 1 pin (+135 V) and 2 pin (GND).
4. Turn on the set.
Power
Supply
SECTION 5 SAFETY RELATED ADJUSTMENT
)
R9901
)
+
1
CN5002
–
2
Fig. 5-1
Remove the cap off
from the unused
terminal and connect a
HV static voltmeter
there.
Fig. 5-2
on the
D BOARD
CN5002
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 disappear).
7. Read the HV static voltmeter of peak HV voltage.
Spec : 33.7 ~ 35.3 kV
8. If Hold-down voltage is less than 33.7 kV then
replace R9901 of 43 k with that of 39 k , and
check if the voltage is within the spec.
9. If hold-down voltage is over than 35.3 kV then
replace R9901 of 43 k with that of 47 k , and
check if the voltage is within the spec.
– 22 –
KP-44PX2/44PX2U
– CONDUCTOR SIDE –
CN5003
Fig. 5-3
CN5003
R9901
Fig. 5-4
RM-938