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Zenith SM276759 - n00b to repairs..

Hi - please don't flame me *too* much, as I'm still teaching myself on the fly - and have done a good bit of mostly confusing research. All I have available to use is a multimeter, which I've done continuity tests with on most of the major resistors and capacitors. Uncertain about how to test caps properly without replacements or the like.

TV is a 27" built around 1994.

Has screen issues - is solid green with rescan lines (I think they're called) running down it.

On screen display and menu shows up still, ironically, but anything else only provides the faintest ghosting.

Messed with the color pots - got expected result; more green red or blue and whatnot, no change to rescan.

Adjusting G2 all the way down gives extremely dark, extremely oversaturated image.

Would appreciate whatever idiot-level help I can get; this stuff is a lot like Linux; you've gotta know 15 things just to learn one new aspect.

Reply to
teh.supar.ea
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1994 to 1997 Zenith were famous for having picture tubes that shorted and what you describe is that symptom

Reply to
nipperchipper

You presume wrong.

Reply to
Homer J Simpson

Honestly, I wouldn't touch sets with those CRT 8 years ago and I'm sure they haven't improved with age.

There should be a date on the CRT. If it's the original 1994 CRT, there's no point in continuing unless you can replace the CRT.

The shorts in those CRTs are usually cathode to G1, not heater to cathode (so an isolation transformer won't fix it). Even if you could get rid of the short, the emission is probably too low to produce a good picture.

Don't let the set run with a bright raster because it will blow the power supply. Turn the screen control on the flyback down if you must run it.

These sets used to come in dead with blown power supplies. After fixing the power supply, you'd get anything from a poor to fair quality picture, but eventually the CRT would short again and blow the power supply. Andy Cuffe

snipped-for-privacy@gmail.com

Reply to
Andy Cuffe

Appreciate the clarification. Sounds like this thing is fubar - will likely strip it for components I can use elsewhere and donate it to the local garbage workers' job security fund. :p

Considering I got it for free, it's more than been worth acquiring, if only for experience.

Reply to
teh.supar.ea

If it has a consistent short it may be blown by discharging a charged capacitor. Shorts inside CRT gun can be found with multimeter unless they are intermittent, just check continuity between all pins, only heater pins should read some continuity. Then look inside the glass and follow the connections to identify what is what. Some CRT manuals with pictures on the net may help you learn the parts that make up a CRT gun. I've seen some tubes have two pins connected inside for no apparent reason.

Reply to
Jeroni Paul

That's normally true, but considering the quality of these CRTs, it's pretty pointless. These CRTs have a manufacturing defect that causes them to short and lose emission. Even if you could make it as good as new it would only last a year or two. Andy Cuffe

snipped-for-privacy@gmail.com

Reply to
Andy Cuffe

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