Kent T and Dave A joined the short list of professed 21CT55 "caretakers" which include John T, Steve K, Bob G, Tom S and Steve M, the one at the Early TV Museum? All have already or are about to completely restore these rare RCA second production models to original condition, operating to original RCA specification. The obvious exception is Tom S since I have no intentions of restoring mine to original. I have no cabinet or 21AXP22 CRT, only the front panel, the CTC2B chassis and two 21FBP22 CRTs.
I decided in October 2007 to reactivate the beast after 40 years in attic storage and use it as a test bed to determine and demonstrate in photos, the picture quality this 55 year old RCA 2CT2B chassis was capable of producing. As such, it was not constrained to replicate the original circuitry in every detail or even operate to the '55 RCA spec. I jacked up the +400v B++ supply to above +420v with silicon diodes and got a horz boost of almost 1KV. I intend to start reducing the CRT Ultar HV from its present 34KV to the 28KV range while doing a full convergence at each reduction level to determine if I loose ANY picture quality.
Since I'm ruining the 21CT55 as a composite monitor, I disabled all the tuner, RK/IF and audio portions and opened all unnecessary tube 6.3v heater strings to allow the power transformer to run much cooler. I left all inactive tubes in their sockets and documented all changes for immediate reactivation. Yes, I brutalized this valuable historical item but there are at least five other 21CT55 restorations on this forum alone. I believe I've succeeded in my goal of demonstrating the 21CT55's ability of displaying exceptional picture quality.
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I do intend to refinish the surviving front panel of the original cabinet using the approach described by Bob G in his impressive restoration. I might even attempt to construct a pseudo pencil-box control panel. Tom