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Thomson TV - bright white causes screen to bounce?

David James (Mostly Harmless) posted this on Friday, 18th April 2003, 19:20

Just wondered if any one can help...

I have a 28" Widescreen Thomson. Cable TV box and DVD plugged into it. When there is a bright white (eg explosion), when the next frame is darker.. the screen bounces (looses vertical hold).

Any ideas? Had the TV for 5 months..

Thanks

RE: Thomson TV - bright white causes screen to bounce?

Jon Bayliss (Mostly Harmless) posted this on Tuesday, 22nd April 2003, 10:26

I`ve seen the same thing through my vcr (cheapo Thomson one). I`ve heard the internal circuitry just can`t handle the sudden bright/dark combo. I thought it was my TV to start with, but it doesn`t do it through the DVD player, only on video tapes. If it only does it watching DVDs (as opposed to off-air transmissions/vid tapes etc) it`s more likely the player.
Apparently it`s a known problem with some models of Cyberhome players.

Not much you can do really

RE: Thomson TV - bright white causes screen to bounce?

gingerone (Elite) posted this on Tuesday, 22nd April 2003, 11:52

It`s normally because the power supply within the tv is too weak. Bright images use more power so if the power supply is not sufficient it causes a bounce.

This item was edited on Tuesday, 22nd April 2003, 12:52

RE: Thomson TV - bright white causes screen to bounce?

David James (Mostly Harmless) posted this on Tuesday, 22nd April 2003, 15:31

I have bought a new DVD player recently (at the weekend). A pioneer 656. Havent had a chance to try it on my TV (I took it in for the shop to look at)

will report back.. when I get it back! thanks

RE: Thomson TV - bright white causes screen to bounce?

David James (Mostly Harmless) posted this on Sunday, 27th April 2003, 17:47

the havent been able reproduce the `bounce`

so i have lent them a few DVDs and a VCD i recorded (that just alternates from full white to black screen).

have also asked if I can part ex my TV!

After buying the 656 and a decent scart cable... think my TV lets the rest down!

RE: Thomson TV - bright white causes screen to bounce?

David James (Mostly Harmless) posted this on Sunday, 1st June 2003, 17:01

They had my TV for 3 weeks.

I recorded a VCD which just contained two images... a white square (that filled 80% of the screen) and a black one.

When viewing the white one all is crisp.. skip to the black... again nothing to report.

But when you skip back to the white, the images distorts (wobbles at the sides), no roll this time though.

My brother has the same model of TV done the same test, his does the same thing (but far less wobble).

I tried the same test on a cheap BUSH tv.. and that remained stable?!

The TV is 6-7 months old now, still under warranty.

I spoke to the place where I bought it from, and they say it must be something to do with my surroundings??

Any advice?

RE: Thomson TV - bright white causes screen to bounce?

Chris Muriel (Competent) posted this on Sunday, 1st June 2003, 17:56

Tell them about your tests with the Bush.
Then explain to them that either the power supply was never "stiff" enough
or a component must be faulty.
It may be as simple as needing a larger smooothing or reservoir capacitor on the relevant power rail .
Since it`s a bit of a "low-end" TV, it was probably under-designed in the 1st place.
You could use the services of a qualified electronics engineer (like wot I am) to back you up & fight your corner for you.

Chris Muriel, Manchester.

RE: Thomson TV - bright white causes screen to bounce?

David James (Mostly Harmless) posted this on Sunday, 1st June 2003, 18:01

Thanks for your reply, I will see what they have to say.

The bush was a very cheap TV... the thomson cost 150quid more.

I just didnt expect this bounce.

Thanks again.

RE: Thomson TV - bright white causes screen to bounce?

Davy Moore (Mostly Harmless) posted this on Wednesday, 4th June 2003, 13:27

I had the same problem with my Thomson 32". I had it for about three years and then out of the blue it started displaying the exact descriptions you describe during DVD replay ie. during explosions or sudden change in brightness, the screen would go dark and lose vertical hold. Nothing in my system had changed at this point.

For some reason the problem is not apparent for Sky or video sourced pictures.

Strange. Still, it did give me the excuse to purchase a lovely 32" 100Hz Tosh.

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