Dry joint on 28" Hitachi wide screen TV?

[T i m]

Hi All,

A mate has given me his 5yr old 28" Hitachi wide screen TV and it comes with an intermittent fault where it just cuts out.

Apparently if it does this you can *sometimes* switch it back on with the remote and sometimes not.

He said if it fails to come back on, lifting one corner and dropping it (gently?) often sorts it out?

I had a quick word with the guy in the local electrical shop today and he suggested this was not an unknown fault on that and smaller models in the range and of that age.

So, before I start tapping about all over the place looking for dry joints, any TV gurus out there have any idea if there is a 'common' area that I could start with please?

If I do get it all sorted I will probably give it to my elderly Mum / Dad.

All the best ..

T i m

[bigcat]

I used Unibond bathroom and shower sealant from the local shed. Expensive at 8 quid a go but it's so bloody waterproof it's v.difficult to smooth it after application 'cos it sticks to

*everything*. Flexible too, the only thing that broke it in our case was for some reason the shower tray managed to drop a few mm (don't ask why, I dunno yet!) and the stuff stretched and broke the grout on the surrounding tiles resulting in much leakage.....

The moral to this tale is if yer tray doesn't drop this stuff is good! IMO obviously.

cheers

witchy/binarydinosaurs

[manatbandq]

Look around the flyback transformer. I was told (by the man who repaired one of my TVs with this kind of fault) that the amount of copper in that area makes a very efficient heatsink and makes reliable soldering difficult.

MBQ

[The Natural Philosopher]

I had a set like this once.

It had eyelets rivete through teh board to provide 'through hole' connections.

After soldering up a copule, I decide that an hour soldering every single one on both sides of the board, would be quicker than trying to find which one it was.

The set did another 5 years before it got struck by lightning, and finally died.

On another note, regular readers here may remember me rambling on about a sony TV suffering from green screen/flyback lines/PSU shutdown.

I used to bash it hard, it was getting worse. Cassandras prophesised that it would finally fail as the tube was going.

In fact, for some unexplained reasn, it has performed flawlessly for the last 6 months.

[bigcat]

Perhaps a tube short burnt out or fell off? Burning shorts out is a standard repair after all, and the associated psu shutdown suggests possible high fault current. Who knows :)

I once experimentally ran a Sony tube fairly heavily overvoltage (heater +70%, drive V increased, and 10% EHT boost), and it did this fairly regularly. The tube would arc over and so on. It was the only tube I saw that turned PAL into Never The Same Colour Twice :) Dont think I'd do that sort of thing now though :)

NT