Quote:
Originally Posted by Kevin Kuehn
That dome is pretty crude, as in not very round. Plus the back is all perferated even upto the dome. Could be a later mod?
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My guess is that the set and its back were originally designed for 17AP4, but midway through production, DuMont decided to use 17BP4. They did a factory rework on the backs, adding the dome. The backs had already been perforated in the area of the dome.
The tube label on the inside of my set specified 17BP4, so at least they updated the labels.
The tube in mine was an RCA, with very strong emission. Perhaps that was a replacement, with a DuMont 17BP4 being stock.
If this tube won't come to life, I don't think you will have much trouble finding another 17 inch tube. There are a lot of 17 inch sets out there that are far less worth saving than a DuMont. 17LP4 was a pretty common tube; not sure if it has the correct deflection angle.
I'm not so conservative on rejuvination. Had good success with it several times, and don't recall ever making a tube a lot worse. Some tubes simply won't rejuvinate, but I suspect they are beyond rescue no matter what.
If you're up to the good/bad line at 8 volts, however, you may be fine with a brightener now. I'm often surprised at how good the picture looks on tubes that test in the ? range.
10-21-2011, 08:53 PM
Hybrid Mode
