Service manual

PV151 PROJO
PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO-VIDEO PRODUCTS
CHASSIS HIGH VOLTAGE ADJUSTMENT PROCEDURE
1. Connect High Voltage meter to FBT High Voltage out-
put. Connect Ground of High Voltage meter to CRT
Ground or FBT Ground.
2. Check that the High Voltage adjustment VR (RH44) is
set to it’s mechanical center on the Deflection PWB.
This VR is located just behind the Flyback transformer
as viewed from the Front of the set. (See diagram be-
low)
3. Receive an NTSC generator signal. (Picture should be
stationary for this adjustment.
4. Video Controls should be set to Factor Settings.
5. Adjust the High Voltage to the following specifica-
tions by turning RH44 slowly.
6. Lock Paint the control. If available.
RH44
High Voltage ADJ.
FBT
TH01
CHASSIS HIGH VOLTAGE LIMITER CHECK
Check Preparation:
1. The set can face any direction.
2. Receive the Cross-Hatch Signal
3. VIDEO CONTROLS: Brightness to Maximum.
4. SCREEN FORMAT: Should be PROGRESSIVE mode.
5. Attach the JIG (1k ohm 1/8W resistor) to both ends
of DH31 as shown in the diagram below. (See Diagram
Below)
RH54
RH55
CH30
DH31
DH24
+50V Pulse
Add JIG to check Hi
Volt Limit Circuit
JIG = 1k ohm 1/8W
Checking Procedure :
1. Check that the picture is turned off and the horizon-
tal deflection circuit stops operation.
After Checking:
1. Unplug set and Remove Jig. Allow set to remain in the
off condition for at least 15 seconds.
2. Apply AC and confirm the set returns to normal opera-
tion.
CHASSIS FLYBACK PROTECTION CIRCUIT CHECK
Check Preparation:
1. The set can face any direction.
2. Receive the Cross-Hatch Signal
3. VIDEO CONTROLS: Factory Preset.
4. SCREEN FORMAT: Should be PROGRESSIVE mode.
5. Attach a 100 K ohm 1/16W ~ 1/8W resistor between
QP02 base and Gnd. (SD4 connector Pin 4) and check
operation.
After Checking:
1. Unplug set and Remove Jig. Allow set to remain in the
off condition for at least 15 seconds.
2. Apply AC and confirm the set returns to normal opera-
tion.
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