[Milsurplus] Capacitor Question

[Marty Reynolds]

>> .... The parts list
>> says
>> they are mica even though some are as high as .01 mfd (10,000 mmfd).
> Are they really mica?  - Probably not.  Break one open, and look.
>
> Are they reliable?  - Papers are probably NG.  Micas are possibly
> tolerable.  I probably wouldn't resort to wholesale replacement of micas
> unless I started finding leaky ones.
>

complete agreement

I'd add this tho.  Make sure no filament supply.  Apply more than design
B+ to rx thru a current limited supply.  Like 400vdc w. seriesed 25K
resistor.

Measure drop across resistor & if zip, you & the purported micas are fine.
If big drop, look @ ckt. for shunt across B+ line.  If found then lift it
& try again.

If drop still there, start rattling thru all B+ isolation resistors to
ferret bad bypasses.

I reported this months back as a fast way to revive a long-dead BC-455. 
Found only one bad "in-can" bypass.

Recent example is a BC-224 fm weeks back.  Old one, BC-224h by RCA - sn
98.  Must have been in a lean-to for years.  Lotsa outside mud.  But
after lifting RF gain ctl fm gnd, NO drop across current limiter R!!!

She was listening to a classical mix on 1690AM right away.

BUT prior bug-a-boo.  BIG ONE.  Former owner rewired for 6vac & getting
it back to work on 12vdc (yes dyno) took my 1st ever need for set's wiring
diagram.  Don't think I cudda w/o it.  THANKS BAMA/edebris for
having it!!!

Oh and prior guy no dummy - grounded B- BUT removed 41 and pinned out
audio to outboard amp.  Something presumably w. better audio iron.
So think he used 224 as hi-fi s-w tuner

   Marty the 'rm