Hitachi 50SBX78B Projection Television User Manual


 
TECHNICAL CAUTIONS
High Voltage limiter circuit operation check.
1. Turn off TV and connect jig as shown in Figure 2. Adjust
jig fully counter-clockwise for minimum resistance.
2. Set the AC input to 12OV AC and turn on TV.
3. Confirm test pattern on CRT is a usable picture, then
slowly adjust jig until the picture disappears and TV shuts
down.
4. When the limiter circuit is operating properly, High
Voltage will be less than 36.5 kV at 0.6mA when TV shuts
down.
5. Turn off set immediately after checking circuit operation.
6. Unplug set for one minute to reset shutdown circuit.
Remove jig and voltmeter.
Chassis ground
High voltage
connector
Deflection P.W.B.
High impedance
H.V. meter
FBT
(T702)
(Disconnect the # @ pin of 1905 from +B line.
Connect jig (15kQ VR) between +B line and # @ pin of 1905)
1905 #l pin
I
POWER/DEFLECTION PWB
Jig
Fig. 2. Deflection/Power P.C.B.
IO