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CIRCUIT CHECKS
HIGH VOLTAGE
CHECK
CAUTION: There is no HIGH VOLTAGE ADJUSTMENT on this chassis. Checking should be done following the steps below.
1. Connect an accurate high voltage meter to the anode of the picture tube.
2. Turn on the receiver. Set the BRIGHTNESS and CONTRAST to minimum (zero beam current).
3. High voltage must be measured below ® kv.
B
v9
Pete
4, Vary the BRIGHTNESS to both extremes to be sure the high voltage does not exceed the limit under any conditions.
CAUTION:
When the following parts fail, check the High Voltage after replacing.
Location
Name
Name
T461Z | Flyback Trans.
TFB3078ZD
D489 | Zener Diode
MTZJ3.6B
Q480 | Transistor
28C2023LF-4
Q483 | IC
TA75458S
R435
Resistor
33k ohm, 5%
R489
| Resistor
3.3k ohm, +5%
R490
| Resistor
3.3k ohm, +5%
R450
| VR
1k ohm
C440
| Capacitor
1000pF, +3%
C443
| Capacitor
C444
| Capacitor
OpF,
+3%
ANODE VOLTAGE
MEASURING
METHOD
CAUTION: Take extra precaution when measuring this high voltage. High voltages are also present in surrounding circuit
boards (CRT DRIVE assembly, DEFLECTION assembly, and POWER SUPPLY assembly).
1. Disconnect the FBT anode cable as outlined below. Measure 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 _
28.)
. Determine the extent of the rubber cover before disconnecting the cable.
. Pull straight up the anode cable to disconnect.
. When reconnecting the cable, proceed in the reverse order.
After reconnecting, tug on the cable to check that it is secure.
OER
No.51281
29
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