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Service Adjustments
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Service Adjustment-4
HIGH VOLTAGE CHECK
Note: +B (+130V) Voltage and Grayscale Adjustment must
be completed before attempting High Voltage Check.
1.
Connect high voltage voltmeter negative lead to
ground, and c lead to anode of picture tube.
2.
Tune receiver to an active channel and confirm TV is
operating properly.
3.
The high voltage must be 25KV ± 1KV and less than
28KV at 0 beam current (Brightness and contrast
minimum setting).
Note: If the picture tube is replaced, check the high
voltage.
This TV set has a built-in power supply protection circuit.
It is provided to protect the TV set in case of a power
supply circuit malfunctions. When something abnormality
occurs during TV reception, the TV set goes to the stand-
by mode.
When an abnormality occurs during TV reception,
it causes pin 23 of the CPU to go continually Low
voltage for about one second. The CPU detects
that this has occurred and outputs the signal from
pin 36 to switch off the power supply lines.
Releasing the protective circuit and restor-
ing power supply
To release the protective circuit and restore power supply,
turn the power to the TV set OFF and then ON again via
either the main power switch or the ON-OFF button on
the remote control. This will work only if the power supply
trouble was temporary. If there is permanent trouble such
as a damaged circuit, power cannot be restored and the
circuit will have to be repaired.
Protection Circuit
FOCUS ADJUSTMENT
1.
Receive the monochrome circular pattern.
2.
Set the brightness to normal and contrast to maxi-
mum.
3.
Adjust the focus control on the F.B.T. for the best
focus on the screen centre.
FOCUS VR
(Upper side)
