Safety Related Adjustments; Hv Regulation Circuit Check And Adjustment; Hv Hold Down Circuit Operation Check And Adjustment; B Max Voltage Confirmation - Sony KP-HW51K90J Service Manual

[ D BOARD]
5-1. HV REGULATION CIRCUIT CHECK AND
ADJUSTMENT
ollowing components marked with
When replacing the f
schematic diagram always check HV regulation, and if neces-
sary re-adjust.
: VR8001
: C8079, C8083, C8090, C8129, D8013, D8015
D8038, D8043
IC8006
Q8021, R8055, R8099, R8102, R8128, R8129,
R8131, R8139, R8140, R8142, R8153, R8163,
R8223, R8230
T8004 (LOT), T8005 (FBT)
HV block, D board
OPERATION CHECK
1. Receive the all white signal.
2. Set PIC MAX/BRT CENT.
3. Confirm that the voltage between CN8015 1 PIN and GND
is less than 7.80VDC.
HV REGULATION ADJUSTMENT
1. Connect a HV static voltmeter to the unconnected plug of the high-
voltage block.
2. Power on the set.
3. Repeat steps 1 and 2 as above.
4. Confirm that the static voltmeter reading is 31.0 ± 0.4kV.
5. If not, adjust with VR8001 to the specified value.
6. After adjustment, put the VR cover on VR8001 as shown below and
apply sufficient amount of epoxy resin around VR8001.
Fig. 4-1
Fig. 4-2
SECTION 5

SAFETY RELATED ADJUSTMENTS

on the
Remove the cap off from
the unused terminal and
connect a static voltmeter
there.
epoxy resin
VR8001
5-2. HV HOLD DOWN CIRCUIT OPERATION
CHECK AND ADJUSTMENT
When replacing the following components marked with
the schematic diagram always check hold-down voltage and if
necessary re-adjust.
: VR8002
: C8054, C8086, C8088, C8100, C8104,
C8118, C8123, C8124
D8019, D8020, D8022, D8028, D8036
FB8001
IC8008
Q8035, Q8038
R8035, R8043, R8159, R8166, R8171,
R8196, R8201
T8004 (LOT), T8005 (FBT)
HV block, D board
OPERATION CHECK
1. Receive the dot signal.
2. Set PIC MIN/BRT MIN.
3. Confirm that the voltage between cathode of D8038(JW171)
and GND is more than 23.0V DC.
4. Using an external DC Power supply, apply the voltage shown
below between cathode of D8038(JW171) on "D" and GND,
then confirm that the HV-Prot circuit works.(Raster disap-
pears.)
Apply DC voltage: Less than 29.05V DC.
HV HOLD-DOWN ADJUSTMENT
1. Connect a HV static voltmeter to the unconnected plug of the high-
voltage block.
2. Power on the set.
3. Connet an externel 10kΩ VR at CN8015 and adjust this VR so that
the high voltoge is 34.50kV.
4. Adjust VR8002 to the point that the HV-Prot circuit works (Raster
disappears) at 34.50 ± 0.50kV reading on the static voltmeter.
5. After adjustment, put the VR cover on VR8002 and apply sufficient
amount of epoxy resin around VR8002 as the same manner for
VR8001.
[ G BOARD]

5-3. +B MAX VOLTAGE CONFIRMATION

The following adjustments should always be performed
when replacing IC501, R5032.
1. Supply 130VAC to variable autotransformer.
2. Receive dot signal pattern and set the PICTURE and
BRIGHTNESS settings to their minimum.
3. Confirm the voltage of TP +B 135V is less than 137.0Vdc.
4. If step 4 not satisfied , replace IC501 and repeat above steps.

5-4. +B OVP CONFIRMATION

1. Add to low voltage power supply between to TP. 5001 and
ground.
2. Supply 120VAC to variable autotransformer.
3. Power on the Set and receive dot signal pattern.
4. Set the PICTURE and BRIGHTNESS settings.
5. Check the OVP is activated.
Operate :less than 2.50V
– 33 –
KP-HW51K90J/HW57K90J
RM-Y909K
RM-Y909K
on