Unstable vertical hold and buzzing on sound on tv

[Martin]

The tv is a Contec colour tv. Picture is randomly unstable
vertically and a buzzing noise is superimposed on the sound.
This happens as soon as the tv is switched on. The symptoms are:
holding for a few seconds and then fast rolling; sometimes stopping
and holding halfway with a half inch gap separating the top and bottom
of the picture running across the centre of the screen with what I'd
call 'noise' in this gap - thousands of white flecks filling this half
inch gap (don't know if that's normal, but it looks as if it is
associated with the buzzing coming out of the speaker).

I have checked for and fixed bad connections and also replaced the
vertical sync IC without effect.

Any suggestions for further troubleshooting the faulty component very
much welcomed.

Martin

 

[Sofie]

Martin, you might want to now focus your attention on the PS........ check
the electrolytics for high ESR and replace as needed....... also check and
replace if necessary the regulator.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Martin" <vdp3r@hotmail.com> wrote in message
news:544b97f8.0312181104.559002f2@posting.google.com...

The tv is a Contec colour tv. Picture is randomly unstable
vertically and a buzzing noise is superimposed on the sound.
This happens as soon as the tv is switched on. The symptoms are:
holding for a few seconds and then fast rolling; sometimes stopping
and holding halfway with a half inch gap separating the top and bottom
of the picture running across the centre of the screen with what I'd
call 'noise' in this gap - thousands of white flecks filling this half
inch gap (don't know if that's normal, but it looks as if it is
associated with the buzzing coming out of the speaker).

I have checked for and fixed bad connections and also replaced the
vertical sync IC without effect.

Any suggestions for further troubleshooting the faulty component very
much welcomed.

Martin