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Old 12th Nov 2017, 4:13 pm   #61
kalee20
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Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,061
Default Re: Oh No! Not another howler.

Quote:
Originally Posted by Boater Sam View Post
Please see post 47.
Thanks! Actually, this (and other posts) came up while I was preparing my own post 49. It's a lively thread!

Quote:
Originally Posted by Argus25 View Post
Probably most AC41's don't do it, but with a borderline condition such as a subtle amount of tube gas or heater cathode leakage, its enough to trip it off. I agree though, all the usual suspects should be checked first. It might be though that in this set, one of the IF coils was made with accidental reverse polarity, could be just enough to do it in conjunction with other factors.
Really good suggestion! In that case, the thing would always have been howl-prone.

Or could be TATG oscillator action, as Lawrence says.

Boater Sam has made it clear he's a chap with knowledge and experience, and even so, he's stumped so far! It almost sounds like there is borderline design, in which case we need another AC41, as-manufactured, just for comparison!
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