20/21V-L110M
INSTALLATION AND SERVICE INSTRUCTIONS
Note:(1) When performing any adjustments to resistor controls and transformers use non-metallic
screwdrivers or TV alignment tools.
(2) Before performing adjustments, the TV set must be on at least 15 minutes.
CIRCUIT PROTECTIONHIGH VOLTAGE CHECK
The receiver is protected by a 3.15A fuse (F701),High voltage is not adjustable but must be checked to
mounted on PWB-A, wired into one side of the AC lineverify that the receiver is operating within safe and
input.efficient design limitations as specified checks should
be as follows:
+B DC REGULATOR CONFIRMATION
1. Connect an accurate high voltage meter between
The +B DC output voltage adjustment is not includedground and anode of picture tube.
in this circuit. However, should confirmation be2. Operate receiver for at least 15 minutes at 110~230V
required proceed as follows.AC line voltage, with a strong air signal or a properly
tuned in test signal.
1. Actuate receiver with 230V AC input voltage.3. Receive a good local channel.
2. Receive a local channel.4. The voltage should be approximately, 25.5kV (at
3. Connect positive lead of digital voltmeter to C754picture MAX bright center condition). 20V-L110M.
positive side on PWB-A; negative lead to chassisThe voltage should be approximately, 26.0kV (at
ground.picture MAX bright center condition). 21V-L110M.
4. Confirm this voltage reading is as below.If a correct reading cannot be obtained, check
CAUTION: The reading should be within +130.0 ? 2.0Vcircuitry for malfunctioning components.
DC to ensure normal function and circuitry
reliability.
X-RADIATION PROTECTOR CIRCUIT TEST
After service has been performed on the horizontal
deflection system, high voltage system, B+ system,
test the X-Radiation protection circuit to ascertain
proper operation as follows:
1. Apply 230V AC using a variac transformer for
accurate input voltage.
2. Allow for warm up and adjust all customer controls for
normal picture and sound.
3. Receive a good local channel.
4. Connect a digital voltmeter to TP653 and make sure
that the voltmeter reads 21.4 ? 1.5V.
5. Apply external 27.9V DC at TP653 by using an
external DC supply, TV must be shut off.
6. To reset the protector, unplug the AC cord and make
a short circuit between TP651 and TP652. Now make
sure that normal picture appears on the screen.
7. If the operation of the horizontal oscillator does not
stop in step 5, the circuit must be repaired before the
set is returned to the customer.
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ACEC
