Hi all,
Having a Panasonic television CT-27... with a color problem. There is a kind of big circle on the screen and the color is not right around thiscircle. King of purple and yellow.
It looks like a perfect circle so I'm assuming something in the tube itself is bad. Shadow mask ? Problem with the Degauss ?
Any idea ?
Tks for you help...
someone probably put a speaker or other magnet against it or it is impact damage.try replacing the degauss posistor first.
-B
The built in degauss won't fix a bad case. Needs external degaussing. A repair shop should be able to do this.
Was it dropped?
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The unit dhas not been dropped and no speaker has been put near the TV.
Unit was OK and went bad just like that.
You can easily see a big circle >
In that case I would say that either the degaussing circuit has failed, or the deflection yoke is loose and has slipped back on the neck of the CRT. Both of these problems are minor and will cause the problem you describe. Manual degaussing won't fix either of these problems. Andy Cuffe
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in some cases moving of scan coils back can result in tube explosion.
NT
In some cases dropping a CRT onto concrete can result in breakage, Huh??
Bruce
Circular magnetic effects are usually due to the degaussing circuit malfunctioning or a power surge such as happens with a nearby lightning strike. The former is very common on Panasonic sets, could be bad solder connections at the degaussing thermistor or a bad thermistor.
If it is the latter problem, manual degaussing may be needed.
Leonard
Hi All ,
The thermistor has been tested OK and solder joints are OK.
How to confirm that it's not the tube ? Shadow mask ?
Should I try to degauss it anyway ?
Tks for you help...
You may have had a nearby lightning strike? We see sets all the time that have been subjected to a surge that have the tube magnetized by the degausing coil to the extent that the internal degaussing cannot demagnetize the tube.
The fact that it is circular indicates that the source of the magnetic field is likely the degaussing coil itself. A damaged CRT shadow mask will almost always give you adifferential symptom at the edges on one side.
Leonard
Right on !
I use an external degauss coil and it's OK now.
Tks.
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