Ralph S
06-16-2009, 05:30 PM
I'm kinda stumped: I've been going through the 1955-1966 RCA Field-Service Guide and of all the models from CTC-2B thru CTC-10 the only one that doesn't have an HV adjust is the CTC-5. The 1956 T6 Service Data is remarkably cryptic, basically saying to measure the current across fuse F104 (with fuse removed, I assume) and set it to something less than 220 ma while watching the HV with a high voltage probe to show a reading somewhere between 18 and 22 KV. RCA also suggested that the usual regulator (6BK4) cathode current be checked to set black to no less than 800 microamps using tuning or detuning of L106; the same coil you use to set the current at F104. This seems to be a rather indirect way of going about things. Wouldn't it make some sense to put in an HV adjust pot of say 500K along with a series fixed resistor of 1.5 meg in place of R125, a fixed 1.8 meg resistor (grid to ground path?)
Another question: Why is it that of all the various RCA models which used the 21AXP22, the 5 seems to have the lowest HV? Are they trying to tell us something from the corporate grave?
Also: Of much less significance than the above: Does someone out there have one of the Bakelite 45 degree high frequency speaker supports for the "Panoramic" tweeters in the Deluxe model CTC-5? Mine was delivered with one smashed and I need to replace it....
Thanks for your help!
Another question: Why is it that of all the various RCA models which used the 21AXP22, the 5 seems to have the lowest HV? Are they trying to tell us something from the corporate grave?
Also: Of much less significance than the above: Does someone out there have one of the Bakelite 45 degree high frequency speaker supports for the "Panoramic" tweeters in the Deluxe model CTC-5? Mine was delivered with one smashed and I need to replace it....
Thanks for your help!