CIRCUIT CHECKS
HIGH VOLTAGE CHECKFS CIRCUIT CHECK
CAUTION: There is no HIGH VOLTAGE ADJUSTMENT onThe Fail Safe (FS) circuit check is indispensable for the final
this chassis. Checking should be done followingcheck in servicing. Checking should be done following the
the steps below.steps below.
1. Connect an accurate high voltage meter to the anode of1. Turn the receiver on.
the picture tube.2. Temporarily short TP- (R) and TP- (X) on the DEF/POWER
2. Turn on the receiver. Set the BRIGHTNESS and CON-Board with a jumper wire.
TRAST to minimum (zero beam current).Raster and sound will disappear.
3. High voltage must be measured below (B) kV.3. The receiver must remain in this state even after removing
the jumper wire. This is the evidence that the FS circuit is
Refer to table-1 for high voltage (B).
(See SETTING & ADJUSTING DATA on page 19)functioning properly.
4. To obtain a picture again, temporarily turn the receiver off
GENERAL ADJUSTMENTS4. Vary the BRIGHTNESS to both extremes to be sure theand allow the FS circuit more than 5 seconds to reset. Then
high voltage does not exceed the limit under any condi-
turn the receiver on to produce a normal picture.
tions.
CAUTION:Troubleshooting Guide for Fail Safe Circuit
When the following parts fail, check the High Voltage after
replacing.
Check that the set returns to normal operation when
pin 12 of Z801 is grounded with jumper wire.
Descriptions
Location
Name
No.50", 65"
YESNO
T461FlybackTFB3092AD
C407Capacitor4700pF, ?3%
Check the voltage acrossFaulty power
C408Capacitor8200pF, ?5%
Capacitor C419 iscircuit or hori-
C441Capacitor4700pF, ?3%
approximately (C) volts.zontal circuit.
C432Capacitor8200pF, ?5%
Refer to table �3 for
SPECIFIC INFORMATIONSC433Capacitor1200pF, ?3%
fall safe voltage (C) .
ANODE VOLTAGE MEASURING METHODYES
(See SETTING & ADJUSTING
CAUTION: Take extra precaution when measuring this high
DATA on page 19)
voltage. High voltages are also present in
surrounding circuit boards (CRT DRIVE assem-
bly, DEFLECTION assembly, and POWER
SUPPLY assembly).NO
Defective Fail Safe Circuit
1. Disconnect the FBT anode cable as outlined below. Meas-
ure high voltage at the point where the cable enters the
FBT.
2. Holding the rubber cover firmly, turn it counterclockwise
and check that the lock has been disengaged. (See Fig. b
on page 9.)
3. Determine the extent of the rubber cover before discon-
necting the cable.
4. Pull straight up the anode cable to disconnect.
5. When reconnecting the cable, proceed in the reverse order.
After reconnecting, tug on the cable to check that it is se-
cure.
� 18 � |
ACEC
