Hey guys,
I noticed on my ctc-16 that there seems to be a green shadow to the right side of images when the color is turned up. Also a wierd thing is that when I use the VCR, channel 3 is adjustable on the fine tuning dial but the colors are off, but channel 4 when the VCR is switched there, the tuning is not adjustable. Bad contacts or possibly a tuner tube? I might need to recap the rest of the set as I only recapped the Filter caps. Pics are from my cell phone. Finally got pics of my set!!:banana:


http://i236.photobucket.com/albums/ff144/freakaftr8/10-16-07_1843.jpg

Looks like a bad case of video smearing. Look to the IF section. There could be an open cap or faulty delay line causing the problem

If you have a sams or schematic, compare voltages on the IF tubes. How are the video detector and amplifier tubes?

Looks like your vertical height is lacking in that screengrab.

Yeah, the Vetical is deffinatly shrinking, cannot seem to find that gnome. Progressivly getting worse, think it's a 2kv .001mfd paper cap on the vertical sweep board. Thanks for that info!

Greetings!
From your photo, it looks like you have some smearing, but only in the chroma signal (assuming black and white reception looks normal.) If I remember right, the chroma circuit board has a bunch of little peaking coils, which like to go open and cause strange color symptoms. These coils look like really thick ceramic capacitors, with the leads installed in such a way that they pass through the body and stick out with little stubs on the top of each part. With your trusty ohmmeter, go on a hunting adventure for coils which are open - they normally measure just a few ohms so when you hit one which shows thousands, you've found the culprit in all likelihood. (You can even take your test measurements at the two little "stubs" that protrude through the part body.)

If you want to do the job right, you'll need to hunt around and find a replacement for any coils found to be open. But I've found the results to be virtually identical simply by replacing the bad coil with a piece of wire. I suspect that if you replaced all the peaking coils in the entire set with pieces of wire, you would significantly degrade the performance, but just a single coil here or there seems to be pretty much un-noticeable.

Good Luck!

Well I checked those peaking coils and they seem to be good.. I noticed that UHF doesnt seem to have the smearing issue.. Wonder if a weak tuner tube can cause this?? Oh yeah, and I tried to degauss the left side of the CRT. Has a bad green tint when a blue backgound shows up, otherwise there is no telling of a color problem when there are other colors on the screen besides blue, wierd stuff, Has anyone had this issue? Seems to be that it actually might not be a degausing issue...

Placement of the deflection yoke can cause corner color blotches. I would perform a complete purity setup (magnets first, then yoke,) then grayscale and see how the color looks then.

If the problem only occurs on VHF then the tuner is at fault. Could be something silly like oxidized contacts, open coil, tube, grounding problem, or someone could have been screwing with the alignment.

Does the fine tuning effect the smear at all?

Yeah when the color goes away, no more smearing. the Purity issue on the left of the screen is bad and it fills up the whole left side about 6" of it. look at the pic in the first posting, you can kinda make it out. Im in process of replacing the paper cap on the IF and vertical board. Hopefully I can fix it

BTW, that screen grab in my avatar is the same set, if it was a degausing purity issue on the left of the screen, wouldnt that show up in the white too?

not always. I always use the red gun to index the purity. unless there's a defect in the shadow mask of the tube (it happens) you should be able to get good purity.

If you get a perfect red raster and there are no tube defects, then the rest of the colors should also be perfect. Make sure you have no magnetic influence near the CRT. This can be speakers, wall warts (power supplies) transformers --basically anything else that can generate a magnetic field.

oh, and since you say the black and white picture isn't smeared, look in the color circuits. Could be something simple like a bad tube in the bandpass amp, chroma demod, or chroma amp. perhaps some more attention to re-capping.

If you have the test equipment and sams I would check the color alignment. If any values are off you may be able to better troubleshoot the problem with the sams and or schematic.

Cool, thanks Jordan!

Hey guys, well I spend a few hundred hours on the ctc-16 last night, still have a green raster to the left of the screen, and shrunken vertical and smeared chroma, but this is what I came up with, using rabbit ears..
Mind that the camera maked the screen look alot brighter than it really is...

http://i236.photobucket.com/albums/ff144/freakaftr8/10-22-07_0233.jpg

I had a zenith with a green left side raster. It turned out to be a faulty convergence rectifier. However, the set had convergence problems too ( couldnt adjust the blue horizontal lines at the left side raster) and repairing the rectifier cured the green sided raster as well. Perhaps try disconnecting the convergence board while the set is on and see if the green goes away.

Hey Doug, well I tried that, vertical went woncky and the green was still there.. All the pots for convergence operate properly..

As long as you're trying various things, here are some guesses based on absolutely no knowledge of the actual circuit:

What controls, if any, affect the green on the left? Horizontal hold? Color control? Some more diagnosis might lead you to a particular cause, like poor retrace blanking, or a faulty component in the color burst gating or something. Similarly, what controls affect the color smear, if any? How about checking the bypass caps in the section where color is taken off of the composite signal?

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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

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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.

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

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?

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.

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...

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.

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..

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

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.

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.

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

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!

Okay, so a few gremlins yet, but for a ~50 year old TV, that's pretty good.

I suspect there may be some more bad caps as well as resistors.

I was wrong.. The black and white picture is smeared too. The tuner is cool now and UHF and VHF are both smeared with color or no color You can really see it on a clear picture... Still have that odd Green left side raster, but this is interesting.. When I use my VCR I have a blue screen before i fire up the DVD player. You can really see the green there. When the color is turned off, it looks like purity issues. Just a tiny bit of green. When I crank the color up all the way, the green turns red, but the blue screen just gets darker and richer in color, the chroma defect walks acroos the picture by turning the color knob back and forth. Someone here told me my yoke could be defective.

oh, and since you say the black and white picture isn't smeared, look in the color circuits. Could be something simple like a bad tube in the bandpass amp, chroma demod, or chroma amp. perhaps some more attention to re-capping.

If you have the test equipment and sams I would check the color alignment. If any values are off you may be able to better troubleshoot the problem with the sams and or schematic.