green shadowing
 

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/f...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!

Peaking coils
 

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/f...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?