CTC-5 No luminance.

[OS X]

I just bought a restored CTC-5 and I'm having a problem with it, I'm getting no luminance but good chroma. I don't know much about color sets so I'm trying to get a idea what might be causing it? The CRT is good so I don't think it's anything with that.

[dtvmcdonald]

There is both chroma and luma drive in those pictures, in approximately
correct ratio. The CRT screen and brightness and drive (per color) adjustments
just need correct adjustment, assuming of course that nothing broke between
restoration and your buying it.

[OS X]

Originally Posted by dtvmcdonald

There is both chroma and luma drive in those pictures, in approximately
correct ratio. The CRT screen and brightness and drive (per color) adjustments
just need correct adjustment, assuming of course that nothing broke between
restoration and your buying it.

Thanks and I'm hoping that's all it is. I guess I need to start with feeding it a direct signal from a DVD player or I might even try and get a signal pattern generator. For how good the CRT tests I do have the brightness and contrast turned up pretty high to get that picture I wouldn't be surprised if the drive controls got bumped somewhere along the line. Also here's a video of it https://www.youtube.com/watch?v=EY3R3IIlJas

[SwizzyMan]

Check the delay line or the 12by7a tube or parts associated with it.

[OS X]

Originally Posted by SwizzyMan

Check the delay line or the 12by7a tube or parts associated with it.

I believe this set has all its original tubes so it very well may be weak. I guess if I can get my hands on a NOS 12BY7A I'll give that a try to start. Also does anyone have the service manual for this set they would like to sell?

[Electronic M]

Originally Posted by OS X

I believe this set has all its original tubes so it very well may be weak. I guess if I can get my hands on a NOS 12BY7A I'll give that a try to start. Also does anyone have the service manual for this set they would like to sell?

Might be time to buy a tube tester.

[Kamakiri]

I gots NOS 12BY7As

[Kamakiri]

Pretty sure he's got one, but I don't think it does many of the post-1960 tubes. We have to get together anyway, he has a GE color portable for me from his recent trip to Detroit

[oldtvman]

That should be fairly easy to trace down with a scope. Straight forward video problem

[miniman82]

Though if the video (Y) amp tubes are weak, a dim raster can be a symptom.

[old_coot88]

Originally Posted by miniman82

Though if the video (Y) amp tubes are weak, a dim raster can be a symptom.

Right you are.

[wa2ise]

All the unobtanium parts appear to be working fine (CRT, flyback, power transformer and such) and what is broken should be easily obtained.

[OS X]

Well finished testing the rest of the tubes there's a fair amount that are weak. Both 5U4's are weak along with a almost dead 3A3, (2) 6AQ5A's,6CB5A and the 12BY7A. Unfortunately now there's a biger issue when I was removing the 6AW8 (and I was being very carefull) The tube socket just crumbled into pieces it was the only tube in the set that already was replaced, being it is the tube directly next to the 5U4's I'm guessing the extra heat did not help it.

[SwizzyMan]

Those cheap phenolic thin wafer sockets do not like heat. Gets to a point when no matter how gentle you may be they are just too brittle and they break.

[Arcanine]

Originally Posted by OS X

Well finished testing the rest of the tubes there's a fair amount that are weak. Both 5U4's are weak along with a almost dead 3A3, (2) 6AQ5A's,6CB5A and the 12BY7A. Unfortunately now there's a biger issue when I was removing the 6AW8 (and I was being very carefull) The tube socket just crumbled into pieces it was the only tube in the set that already was replaced, being it is the tube directly next to the 5U4's I'm guessing the extra heat did not help it.

3A3 tubes always test bad. The testers don't generate the voltage that goes though those tubes. It's still good. Don't sweat it. Get a spare, yes, but even NOS will test bad, too.