Technical Cautions; Circuit Protection - Hitachi C47-WD8000 Service Manual

TECHNICAL CAUTIONS

High Voltage limiter circuit operation check
1. Turn off TV and delete resistor RH19 (82KΩ) in the Power/Deflection PWB, set 50KΩ VR fully clockwise(maximum
resistance).
2. Set the AC input to 220V AC and turn on TV.
3. Confirm test pattern on PRT is a usable picture, then slowly adjust 50KΩ VR until the picture disappears and TV
shuts down.
4. When the limiter circuit is operating properly, High Voltage will be less than 35.6kV(maximum brightness and
contrast).
5. Turn off TV immediately after checking High Voltage limiter circuit operation.
6.Unplug TV for one minute to reset shutdown circuit. Remove the jig A, and then add resistor RH19(82KΩ)to the PWB.
POWER /
DEFLECTION PWB

CIRCUIT PROTECTION

Fuse (or Device)
F901(T6.3AL/250V)
F902(T1AL/250V)
F903(T3.15AL/250V)
F904(2.2Ω/fuse)
FP01(T3.15AL/250V)
FBT
RH19
33 KΩ
RH17
Fig.2 High Voltage limiter circuit operation check
AC POWER CIRCUIIT
STAND BY CIRCUIT
SIGNAL POWER CIRCUIT
SIGNAL POWER CIRCUIT
PRIMARY POWER CIRCUIT
FBT
TH01
Connect Jig A to PWB between RH19
50 KΩ VR
Circuit Protected
7
50 KΩ VR 33 KΩ
Physical Location
Power Supply Unit
Power Supply Unit
Power Supply Unit
Power Supply Unit
Power / Deflection PWB