August 1977 RCA Colortrak

[pac.attack76]

Looks like someone wrote on the back, CTC90D. Anyway, just got this from a guy that was a tv tech who had kept up maintenance for years. It doesn't have any color to it and it has a bit of convergence issue near top. Just looking where to begin. Want to use this set with matching vcr, ced unit and atari.

[pac.attack76]

I've been looking at this for a bit. Due to the move from where I picked it up, an hour away, the yoke had slid back and shifted also causing the purity rings to get pushed back to the socket. I've put everything back up where it should be but I still have nearly no color and convergence is a little off.

[vol.2]

Originally Posted by pac.attack76

I've been looking at this for a bit. Due to the move from where I picked it up, an hour away, the yoke had slid back and shifted also causing the purity rings to get pushed back to the socket. I've put everything back up where it should be but I still have nearly no color and convergence is a little off.

Maybe there's an issue with the color control? I would pull it and check resistance across the pot and make sure it's not flaky.

[pac.attack76]

Originally Posted by vol.2

Maybe there's an issue with the color control? I would pull it and check resistance across the pot and make sure it's not flaky.

The dial at the front behind the door?

[vol.2]

Originally Posted by pac.attack76

The dial at the front behind the door?

I'm not familiar with you're specific set, but there should be a color control on it. When you turn the color down all the way, it should make the image black and white. It essentially is there to let you adjust the chroma subcarrier level.

If there was something wrong with the control, like there was a break in the carbon track, or it was just really dirty, or there was a bad solder joint or something, that could cause a loss of color like you are seeing.

Another thing that could cause loss of color is if the the tuning is off and you are using RF. Sometimes if the tuning capacitors are dirty, that can cause weird effects like loss of color. That generally just requires spraying the tuner and moving it back and forth a bunch. This would only be an issue if you're using RF input, not if you're using composite.

There's plenty of other possible issue though. It could be a bad component in the chroma demodulation section or a bad power supply source voltage for one of those areas. I'm just giving you low hanging fruit to test

[pac.attack76]

Originally Posted by vol.2

I'm not familiar with you're specific set, but there should be a color control on it. When you turn the color down all the way, it should make the image black and white. It essentially is there to let you adjust the chroma subcarrier level.

If there was something wrong with the control, like there was a break in the carbon track, or it was just really dirty, or there was a bad solder joint or something, that could cause a loss of color like you are seeing.

Another thing that could cause loss of color is if the the tuning is off and you are using RF. Sometimes if the tuning capacitors are dirty, that can cause weird effects like loss of color. That generally just requires spraying the tuner and moving it back and forth a bunch. This would only be an issue if you're using RF input, not if you're using composite.

There's plenty of other possible issue though. It could be a bad component in the chroma demodulation section or a bad power supply source voltage for one of those areas. I'm just giving you low hanging fruit to test

Ill check into it. I really don't know at this point. I dont even see tuning. There's only a coax and 2 sets of screws.

[damen]

I believe the black plastic piece around the channel knob comes off for access to the fine tuning pots.

[pac.attack76]

Originally Posted by damen

I believe the black plastic piece around the channel knob comes off for access to the fine tuning pots.

Wow, awesome!! That was hidden well.

[pac.attack76]

No changes with tuning.

[vol.2]

Open up the door at the bottom of that panel and take a picture of the color control. Make the picture larger. Your other pics are too small.

[pac.attack76]

Originally Posted by vol.2

Open up the door at the bottom of that panel and take a picture of the color control. Make the picture larger. Your other pics are too small.

[vol.2]

That's it. What happens to the image when you swing that color pot from end to end? Nothing at all?

The color pot is the one on the top right just to be clear.