green shadowing

[andy]

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[freakaftr8]

Hey guys,
thanks for all your help... I really do appreciate it.
I dont mean to sound dumb, but my simpson milliameter model 260 just came in today, how do I use this against checking capacitors, like orange drops, film, etc...
Thanks

[andy]

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[Adam]

Do you guys know what batteries the 260 uses? I have one I've been using strictly as a volt meter because it's missing all the batteries.

[Bill R]

The 260 may not be the best meter for TV work. The input impedence is not as high as a good VTVM or Digital multimeter. So when you check voltages in the circuit you may not get an accurate reading since the meter can load the circuit. Especially true for alignment work. For alignment you must use a VTVM, Digital meter, or a meter with a very high input impedence.

Bill R

[freakaftr8]

The 260 uses a 9v and a D size battery. Hey I found out of spec resistors. One for instance is a 150k , reading 2.2m ohm!! Can I replace the 150k 10% tolerance with a new 150k 5% tolerance?

[MRX37]

Originally Posted by freakaftr8

Can I replace the 150k 10% tolerance with a new 150k 5% tolerance?

I don't see why not. Infact, the tighter tolerance may be better. I don't know for certain, but I'm pretty sure you can.

[freakaftr8]

Well, i did it... Replaced a 100k resistor that feeds from the +405v to the 1st pin on the green screen, that resistor was measuring 700k. Replaced the 150k resistor that goes between the vert height and vert center. That resistor measured 2.6m. Powered up set. Now I can hear the HV hum and the screen goes all out of focus.. The lights dim in the house. Dont want to risk it so I put the orig. resistors back. Still hums. Think I did some damage...

[radiotvnut]

I'd check and make sure there were no solder "splashes" or "bridges" on the chassis. Also, make sure you didn't damage any wire insulation that might cause a wire to short to something. I can't see where changing two resistors would cause those problems. According to the values you measured on the old one's, they needed to be changed. A capacitor may have developed a short or leakage once the resistors were replaced, thus, causing voltages to rise to circuits that they effected.

[freakaftr8]

Well oddly enough, when I unplug the degausing fiend around the crt, the humming goes away, along with no picture or sound... Im stumped again..

[blue_lateral]

It shuts the power supply down when you do that. The current for the set flows through the degaussing circuit.

I dislike that degaussing circuit. I disabled a few of them years ago. It has two devices, a thermistor and a a varistor (I can't remember which is which). One looks like a carbon disc with wire attached to each side. The other one looks like a giant ceramic cap that has been dipped in tool handle goo. On a 16, this stuff is on the audio board, right by the power supply diodes. Be careful of the carbon-disc looking one. It is very fragile.

A typical failure involves one of the wires falling off the carbon disc thing, then the giant capacitor thing burns, filling the room with nasty smelling smoke. I'm sure a lot of these sets got junked because they convinced their owners that they "caught on fire".

However, I dont really think your problem is there. It sounds like you have a short if the lights are dimming. Double check the polarity on the filter caps if you replaced them. Start at the 405 volt tap, and trace the wiring down through the lower voltage taps on the power supply, looking for anything that could have got pushed/shorted.

John

[drh4683]

Yes, check that audio board and look at the degaussing thermistor. The thermistor is the carbon disk about 3/4" in diameter with the exposed leads that are soldered on each side. Since you had the chassis out, it takes nothing for one of those leads to break free if not both and the whole disk fell out and is now shorting something to ground elsewhere above the chassis. Take a look and see if that thermistor is in place. If so, then id also guess that a solder blob is shorting something out. Im curious why the circuit breaker fails to trip? Those can go bad too though.

[freakaftr8]

You guys were absolutlely right! It was the thermistor! I attemped a repair solder job on it and the set came back to life.. Vertical height is fixed now as well. It was the 150k resistor between the Vert height and center. Thanks guys, youre awesome! Now I gotta go over the IF board. found more out of tolerance resistors for the smearing chroma, although it's smeared in black and white too.

[MRX37]

All right! At least you solved the vertical height issue. Is the smearing image the last gremlin inside that thing?

[freakaftr8]

Kinda, the smearing, the green left side of the screen, another fine tune on the convergence and the crt test. And that's all she wrote!