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Old 07-04-2009, 02:47 PM
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Tomcomm Tomcomm is offline
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Join Date: Nov 2007
Location: Santa Ynez, CA
Posts: 353
21CT55 Warn-up

Bob G........Somehow I didn't realize you were the "Bob" of the recent, most impressive full restoration of all 21CT55s. Since you did a complete recap I would expect yours to have the least problem with warm-up drift. I assume you Quick Freeze'd all resistors in both deflection systems and the complete convergence chassis? I can imagine your frustration when you fire-up your beautiful 55 for some TV-wise visitor and it comes up greatly miss-converged. I have the same problem but I never have demonstrated my 55 to any knowledgeable visitor, so waiting 30 to 60 minutes warm-up before taking critical screen shots is no big deal. I've asked this forum's members that have early RCA tube CTVs if they had similar problems and received zero replies. Must be you and I have a unique problem or others are unaware they have a problem or have little interest in the subject?

I checked my power transformer and horizontal output transformer tempts after over 3 hours operation on 113vac mains input on a hot day. The B++ was 410v, Boost was 900v and ultor was 30kv. The horz output tube input control was set for minimum drive and the horz B++ current was 320ma, horz output transformer was 113deg and the power transformer was 140deg.

I will continue freezing all critical resistors and caps looking for sensitivities as soon as my five cans of quick freeze arrives next week. Of course I will report any interesting results.....Tom
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