Cursitor Doom wrote:

Gentlemen,

I have some old OC171 transistors from an old Eddystone short wave radio
I'm restoring. The problem is I suspect they've developed whiskers, as
the resistance readings from e,c and b to the screen connection are all
far too low (sub 10 ohms). A colleague has suggested blasting the
whiskers by tying the ecb leads together and zapping them against the
screen with a 500nF cap charged to 500VDC. Now this seems a bit counter-
intuitive to me and I'd have thought higher current lower voltage would
be safer for these delicate germanium devices, but WTF do I know?
Is it feasible to remove the whiskers by this sort of method or any other?

I have had some success with an Eddystone EB35 by replacing them with
silicon transistors and adjusting the base bias to get approximately the
same collector current.

(I was a tester on the production line at Eddystones when EB35s were
going through, so I am the one to blame if they don't meet spec.)


--
~ Adrian Tuddenham ~
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