Thread: Rca ctc-5
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  #154  
Old 01-30-2013, 10:16 AM
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Penthode Penthode is offline
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Location: Kitchener/Waterloo Ontario Canada
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Quote:
Originally Posted by Penthode View Post
My thought is the added reactance to the cathode circuit (5ufd cap and wiring) may hinder the ability for th HO tube to be turned off at the end of forward scan. This would reduce the pulse height and inrease the effective series impedance of the HV supply. This is only my thought and I'd next like to explore.
I tried simply grounding the cathode. The was little difference. Perhaps a minor improvement but this was not the crux of the problem.

The CTC5 chassis seems to have HV issues. As Nick pointed out, it may have to do with the B supply. I noticed that as the brightness is advanced to blooming, the vertical scan increases (as would be expected with drooping HV) but the horizontal scan decreases. This suggests the horizontal sweep is has problems.

However, the HO Tube cathode current is low after I minimized it with the adjustment of the efficiency coil. I read elsewhere the that on another chassis the instructions called for a minimum adjustment and then the core was adjusted further into the coil to raise the HO Tube current to the correct value.

Any thoughts on this?
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