25 Nov
2013
25 Nov
'13
2:38 a.m.
On Nov 24, 2013, at 17:43 , Cory Smelosky <b4 at gewt.net> wrote:
What're the components most likely to fail in a
BA23 PSU? I have one that
keeps pouring smoke out of it...yet I can never see a component that's
burnt, punctured, or other stuff like that. I also never hear an arc or
anything exploding. The PSU also squeals when powered down.
What does the smoke smell like? If it smells like burning paper, then look for blocky
translucent yellow EMI filtering caps made by Rifa. I don't have personal experience
with a BA23 yet, but I recently discovered the joy of exploding Rifa metallized paper
dielectric caps in a TRS-80 Model 12. I seem to recall that the same type of cap was one
of the things that blew out in a VCF thread about restoring a PDP -11/44. I now consider
those Rifa caps to be replace-on-sight items, and I'll be replacing them with
metallized polypropylene caps instead of *^!@$#&# metallized paper ones.
--
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/