[R-390] R-390A IF deck caps in T501 or T502

[hamfish at comcast.net]

Larry,

I have one of those Amelco R390/A's. Believe it was little used and original
modules. Serial No. on the IF module is 2062. T501 & T502 appear to be
identical. Starting from top to bottom: a pair of dogbone caps, the two
windings, two resistors, and the two mica caps on the bottom. Tight space
and hard to read, but I see CM115E on the top of the mica caps and 210G03 on
the bottom. There is some color coding on the back, dots. No way to see all
the dots unless removing the caps.

Hope this helps,
Craig 

-----Original Message-----
From: r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> On
Behalf Of Larry H
Sent: Sunday, January 13, 2019 2:53 PM
To: R-390 Forum <r-390 at mailman.qth.net>
Subject: [R-390] R-390A IF deck caps in T501 or T502

I'm working on an R-390A IF deck that has intermittent gain.  I've swapped
all the tubes numerous times, inspected for bad solder joints (found one)
and wiggled all the components and wiring.   I fixed a very bad solder joint
 already in the plate resistor of the 6ak6 v504.  It helped, but did not
solve the problem.

The bug I'm working on now is a bad cap in the T501/T502 in the 2nd IF
V502.  It's heat sensitive - shows up as it warms up.   There are 2 caps on
each coil - I think they are 39 and 15 pf, but the 15 only has writing on it
(no color code) in a form that does not make any sense (115E and 1G03).
It's a small mica and from all the caps I know of, 115E = 1,100,000 pf or
1.1 mfd.  1.1 mfd does not make electronic sense and it is a small mica cap.
The first '1' could be an 'I', as the printing is not real clear, hence my
suspicion it's a 15 pf.  I know it's bad as that coil will not peak and I
replaced the other cap.  I looked through the pearls and parts list, but
could not find the values.  Does anyone happen to know?

I'd really prefer to just replace the 4 caps and not the whole transformer.

Regards, Larry
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