CTC-5 No luminance.

[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.

[OS X]

Originally Posted by Electronic M

Might be time to buy a tube tester.

I do have one and its a rapid tube tester model 82A it pretty much only tests emissions but works ok for a low end tube tester, After looking online for around a hour today I found the tube setup list for this tester as mine is missing at least 1 page and sure enough the 12BY7A is on there, I tested it and it is weak it's on the hi end in the middle questionable area on the tester. I'll try to test all the tubes in this set the tester supports

Originally Posted by Kamakiri

I gots NOS 12BY7As

Look's like the CTC-5 will need one I was able to test it after all and the 12BY7A test weak. And I'll bring your GE over for you as well I got side tracked with the last minute road trip to get the CTC-5 and didn't do much of nothing this past week Lol.

Originally Posted by oldtvman

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

unfortunately I don't have a scope I'm still building my collection of test equipment, right now I only have the very basics. Hopefully a new 12BY7A will help, If not I guess I'll have to get a scope.

[old_coot88]

Originally Posted by 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.

Just to make one point clear: Luminance or 'Luma' refers to the B&W video component of the picture. That is, if you turn the color completely off, there'll still be a normal B&W pic.
Luma doesn't refer to brightness of the raster itself.

[Kamakiri]

Originally Posted by OS X

Look's like the CTC-5 will need one I was able to test it after all and the 12BY7A test weak. And I'll bring your GE over for you as well I got side tracked with the last minute road trip to get the CTC-5 and didn't do much of nothing this past week Lol.

Test all the tubes in the sets you just got and tomorrow you can come shopping.