[Milsurplus] Micamold caps
Al Klase
al at ar88.net
Thu Nov 23 10:57:00 EST 2006
Brad and The Group,
OK, I'll weigh in on this one: REPLACE all the damn MICAMOLD paper caps
(e.g., the rectangular .01 uF's) BEFORE you even turn the radio on.
Don't waste time testing them or fretting over the situation. If they're
not already leaky, THEY'RE GOING TO BE! (Perhaps only a few minutes
after power is applied. If you want to keep the radio original for
posterity, don't play it.
This is based on a lot of first hand experience. If they are grossly
leaky, you'll have toasted screen-grid resistors. Even if only slightly
leaky, you'll have AVC problems.
In most cases, you replace the caps, turn it on, and it plays. There may
still be a problem or two, but they'll be easy to troubleshoot with most
of the marginal components already out of the way.
In the 348's, with the caps on the back of the terminal boards, just cut
the visible lead, leave the cap in place and put a small modern
replacement on the front of the terminal board.
If you do do something like replacing the guts of the originals, leave a
note on the radio so the "next guy" doesn't cut them out.
See also:
http://www.skywaves.ar88.net/commrx/Maintenance/Receiver_Maintenance.html
73,
Al
Brad Latta wrote:
>Just wondering about these black Micamold caps in this
>BC-348. Is it worth replacing them all?? If so,
>is there a modern equivalent with the same size & type
>of mould, & a similar voltage rating? They don't seem
>to have a sharp resonance 'dip' when measured on my
>capacitance bridge.
> Regards, Brad
>
>
--
Al Klase – N3FRQ
Flemington, NJ
http://www.skywaves.ar88.net/
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