Very old GE TV dies- what could be wrong?

ly

I suspect that it could be the power supply not the picture tube but I can be wrong.

Just to be absolutely certain... if you disconnect the TV from the digital box, does it still go dead after a few minutes?

(I'm betting it does, but you'd hate to throw the TV away only to find the problem was the digital box...)

One can't be certain, but I'll hazard a guess --

Assuming it's a color set, it'll have a protective circuit that shuts it down (in order to avoid X-ray emissions) if the picture tube begins to draw too much current. Either that circuit is failing/has drifted out of tolerance, or something else causes the current draw to enter the "danger" zone once the set warms up.

Well the truth is that it could be any one or a combination of several component failures. Since the picture looks ok until it "goes totally silent and black" that does narrow it down a good bit. My next step would be to observe just how it shuts down. Does it appear as if someone just hit the off button? Does it display any anomalies either sound or picture-wise or does it again just look like it was turned off? Does the TV get its AC source from the converter? If it just shuts off like you turned it off I would first suspect the power supply then measure some voltages therein to see what happens as/when it shuts down.

There might also be a cracked solder joint on the board, which is opening and closing as a result of thermal cycling when the set warms up. A bad joint in the right place could shut down portions of the set's power supply.

Yes, the failure is exactly like someone hitting the OFF button.

No anomalies-- it just goes off. However, just recently and only while this problem has been going on, I've noticed that while the TV is briefly working, a station *might* suddenly turn to static- just static sound and no picture. I switch to another channel and all is OK with that one and with the others. [We only get 6 free, broadcast TV channels in my city.]

No, and I've disconnected the TV from the Magnavox HD converter box. The power comes thru the cord plugged into the wall outlet (via an extension cord). Other things connected to this same outlet are fine: a box fan and a clock.

Thanks Meat Plow for your help. Since I never deal with or mess with electronics, I might be able to find someone who knows how to do these tests.

Hi, apart form the other suggestions - don't forget to test the electrolytic caps in the power supply. A dry electro could be the cause too.

Greg

LOL I'm no angel but I'm not K-Man either. Does your buttz still hurt little baby Prongtard?

And I couldn't give a flying f*ck who trusts me or not, Stupid. However I used to do GE warranty work back in the 80's so I know a little about them.

To the seasoned vet those sets are pretty straight forward. I used to do GE warranty among others back in the 80s. I wouldn't sink much money in it however.

ne

ly

nd

nd

The first thing to do is try another tv set in place of your set. if it also fails after a few minutes, then it is the convertor box that is dying. The freezing of the picture is typical of a convertor problem. Magnavox is made by Funai which is the cheapest convertor and has gotten a very bad reputation due to the high failure rate of their convertors.

Bob Hofmann

This television came with a service manual attached in a box on the back. If you could scan and upload the schematic to media fire or a binary group, it might jog my memory. I worked for a high volume GE repair center when that set was new and have probably seen most common failures. Chuck

And your reply jogged my memory a bit. Didn't a lot of those GEs have problems with solder joints on large lugged connections? ISTR a couple of those I worked on back in the 80's (for friends; I was never a commercial tech) which would just 'die'. The fix was to rework all of the solder joints where large 'stuff' was attached to the main PCB.

It seems they didn't get them hot enough, and the larger components (especially chokes and transformers) sinked away so much heat that the joints were not viable. In fact, I recall one on which I had to resort to my 100/150 watt Weller gun to get enough heat going....

jak

I recall feed through points on GE TV boards of that era having sub standard soldering.

Your right, but that issue was resolved by the time the PP chassis came out except for the tuner assembly. Chuck

There was something that would break loose in the switched power supply or the horizontal section and the width pot would burn up and the set would go dead. It was a very common problem but without the schematic, I can't remember what it was. Chuck

Ah ok, it's been awhile. I just recall repairing literally hundreds of those things especially the 19" sets. Got pretty good at it and could knock out a dozen of those a day with few if any reruns. They were actually a good set with VIR and good color. Owned a couple of them bought used from people who left them at the shop for whatever reasons.

Yes Chuck, that's right. There's a cut out window in the plastic box on the back of the TV. Thru the window one easily sees the instructions with words that say the instructions/manual/schematics are only available if the TV box is opened up, something I've not yet done due to what I write below.

When I turned on the TV two days ago, it was totally dead: it wouldn't even start up. So it seems the symptoms I told you about when I started this thread were early signs of eventual TV death which is now the case. Is it still worthwhile to see the schematics? I'd have to open up the TV box and then look somewhere in town for a scanner. [I don't own one.]