#1
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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
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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. |
#3
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Quote:
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#4
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Check the delay line or the 12by7a tube or parts associated with it.
__________________
Admiral C322C2 Regent (Restoring) RCA CTC-7 Pensbury (Restored) RCA CTC-5 Westcott (Restored) CRA CTC--4 Director 21 (Restoring) |
#5
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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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Audiokarma |
#6
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I gots NOS 12BY7As
__________________
"Restoring a tube TV is like going to war. A color one is like a land war in Asia." |
#7
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Might be time to buy a tube tester.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#8
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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
__________________
"Restoring a tube TV is like going to war. A color one is like a land war in Asia." |
#9
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That should be fairly easy to trace down with a scope. Straight forward video problem
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[IMG] |
#10
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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:
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. |
Audiokarma |
#11
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Quote:
Luma doesn't refer to brightness of the raster itself. |
#12
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Though if the video (Y) amp tubes are weak, a dim raster can be a symptom.
__________________
Evolution... |
#13
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Test all the tubes in the sets you just got and tomorrow you can come shopping.
__________________
"Restoring a tube TV is like going to war. A color one is like a land war in Asia." |
#14
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Right you are.
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#15
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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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Audiokarma |
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