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  #1  
Old 01-24-2016, 10:37 AM
OS X OS X is offline
< RCA CTC-5
 
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Unhappy CTC-5 No luminance.

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.
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  #2  
Old 01-24-2016, 10:45 AM
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dtvmcdonald dtvmcdonald is offline
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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.
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  #3  
Old 01-24-2016, 11:00 AM
OS X OS X is offline
< RCA CTC-5
 
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Quote:
Originally Posted by dtvmcdonald View Post
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
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Old 01-24-2016, 11:25 AM
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SwizzyMan SwizzyMan is offline
Restoring an admiral c322
 
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Check the delay line or the 12by7a tube or parts associated with it.
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Admiral C322C2 Regent (Restoring)
RCA CTC-7 Pensbury (Restored)
RCA CTC-5 Westcott (Restored)
CRA CTC--4 Director 21 (Restoring)
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  #5  
Old 01-24-2016, 12:13 PM
OS X OS X is offline
< RCA CTC-5
 
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Quote:
Originally Posted by SwizzyMan View Post
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?
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Old 01-24-2016, 12:17 PM
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Kamakiri Kamakiri is offline
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I gots NOS 12BY7As
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Old 01-24-2016, 02:23 PM
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Electronic M Electronic M is offline
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Quote:
Originally Posted by OS X View Post
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.
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Old 01-24-2016, 04:46 PM
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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
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Old 01-24-2016, 08:59 PM
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That should be fairly easy to trace down with a scope. Straight forward video problem
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  #10  
Old 01-24-2016, 09:49 PM
OS X OS X is offline
< RCA CTC-5
 
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Quote:
Originally Posted by Electronic M View Post
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

Quote:
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.

Quote:
Originally Posted by oldtvman View Post
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.
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  #11  
Old 01-25-2016, 01:39 AM
old_coot88 old_coot88 is offline
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Quote:
Originally Posted by OS X View Post
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.
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Old 01-25-2016, 08:35 AM
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miniman82 miniman82 is offline
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Though if the video (Y) amp tubes are weak, a dim raster can be a symptom.
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  #13  
Old 01-25-2016, 08:47 AM
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Kamakiri Kamakiri is offline
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Quote:
Originally Posted by OS X View Post
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.
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  #14  
Old 01-25-2016, 11:44 AM
old_coot88 old_coot88 is offline
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Quote:
Originally Posted by miniman82 View Post
Though if the video (Y) amp tubes are weak, a dim raster can be a symptom.
Right you are.
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  #15  
Old 01-25-2016, 04:30 PM
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wa2ise wa2ise is offline
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All the unobtanium parts appear to be working fine (CRT, flyback, power transformer and such) and what is broken should be easily obtained.
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