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Magnavox TV 27MS3404/17 Turns On, Then Goes Off

Hi,

I have a Magnavox TV model 27MS3404/17, chassis L01.1UAC-7638 (mfg. 06/05) in my service shop that comes on, picture shows for about two seconds, then the TV goes "off", but the power indicator light stays on. Note: I can turn the TV off "completely" which makes the power indicator light go off.

I checked the HV, and it is around 26KV with picture. With an AC current meter in the 120VAC line, the current drops to around the same level it was when the TV is actually off.

I soldered cold solder joints and replaced C2455 47uf 25V (in horizontal drive circuit) which sometimes causes turn on problems. If you had a similar problem with this model TV, what was the cause?

Thanks in advance, Brad

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Reply to
Brad
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Hi,

Here is more information I forgot to include:

When I turn on the TV, the reg. B+ is 130V (91V in standby). When the TV shuts down (after the picture shows for about 2 minutes), 130V is still present. What is the cause of "shut down"?

Thanks in advance, Brad

Reply to
Brad

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Reply to
lrabanus

Hi Irabanus,

I tried what you suggested, but that did not fix the problem. Note: Sometimes the picture stays on longer than a couple seconds.

UPDATE:

I connected a color bar generator to the TV. Now the TV stays on!!! If I use color bars or any other pattern, the TV stays on!!!! I assume it is due to the steady picture (no changes in brightness, etc.)?

What else should I check?

Thanks in advance, Brad

Reply to
Brad

Hi,

I forgot some information in my "UPDATE". The horizontal sweep system is what is actually "shutting down".

UPDATE:

I connected a color bar generator to the TV. Now the TV stays on!!! If I use color bars or any other pattern, the TV stays on!!!! I assume it is due to the steady picture (no changes in brightness, etc.)?

What else should I check?

Thanks in advance, Brad

Reply to
Brad

The reason it'll stay on with a signal generator on it is that the weak cap in your horizontal circuit can handle it because it doesn't change at all. Look for a little 35v 47ufd cap just off your HOT. I just did one of these... change that cap and you should be good. Can't remember the position, but it's right off the HOT.

Kevin

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