Hitachi C43-FD5000, Service Manual

Page: 6 / 123

6
TECHNICAL CAUTIONS
High Voltage limiter circuit operation check
1. Turn off TV and delete R esistor RH19 （ 82K Ω）
ｉ
n the PWB . Add jig A to the RH19 position in the PWB ， set 50 K Ω
VR fully clockwise( maximum resistance ) .
2. Set the AC input to 24
2
V AC and turn on TV.
3. Confirm test pattern on PRT is a usable picture
， then slowly adjust 50 K Ω VR until the picture disappears and TV
shuts down.
4. When the limiter circuit is operating properly, High Voltage will be less than 36.8KV at 1.6mA when TV shuts down.
5. Turn off TV immediately after checking High Voltage limiter circuit operation. Unplug TV for one minute to reset
shutdown circuit. Remove the jig A
，
and then add resistor RH19
（
82K
Ω）
to the P.W.B.
Fig.2 High Voltage limiter circuit operation check
FBT
TH01
Jig A
50 KΩ VR
33 KΩ
Connect Jig A to P.W.B between RH19.
Deflection/Convergence P.W.B
FBT
RH19
50 KΩ VR
33 KΩ
RH17