Confirm that the horizontal deflection is shutting down (along with the
high voltage since it is derived from horizontal deflection: listen
for the high pitched deflection whine, test for static on the screen,
see if the CRT filaments are lit, turn up the brightness and/or screen
control to see if you can get a raster) and then why:
|NotTaR of Television Sets : Horizontal deflection shutting down
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| TV will not sync >>
- Power is failing to the horizontal output transistor - this could be
due to a low voltage power supply problem, bad connection, etc.
- Base drive to the horizontal output transistor is failing - could be a
fault in the horizontal oscillator or bad connection.
- Problem with the flyback transformer or its secondary loads (flyback
may provide other power voltages).
- X-ray protection is activating - either due to excess HV or due to a
fault in the X-ray protection circuitry.
If the problem comes and goes erratically it sounds like a bad connection,
especially if whacking has an effect. If it comes and goes periodically,
then a component could be heating up and failing, then cooling, etc.