[Boatanchors] Re: [Milsurplus] More 2X2

[carolew]

Tube failures at weird times can drive you nuts!!!

I was working on an SX-28 about a month ago. I had replaced all five
electrolytics and the set played surprisingly well. My next step was to
work on the 2nd AF (ie., replace all paper caps, test all resistors and
replace any out-of-spec resistors). I replaced the coupling caps (always
leaky) and tested the set. Nothing. I mean, nothing.

I immediately assumed that I had made a mistake in replacing the
coupling caps. I examined them with a fine tooth comb. The connections
were correct. No cold solder joints. All voltages on the 2nd AF were
normal. I was pulling my hair out (and combining expletives in rather
picturesque combinations).

After about an hour, I found the problem. It wasn't anything I had done
in the 2nd AF. Rather, it was  a 6B8 tube in another stage that had
failed at an inopportune moment. A new tube made the set play
wonderfully.

There's a lesson in there somewhere.

Joe Connor