[R-390] 16 KHz filter oscillates

[rbethman]

Tisha,

That really becomes an issue of *when* the radio was manufactured.

Going back to the Cost Reduction Analysis Report - ONE of the top items 
of cost concerns was CAPACITORS.

I have on the bench "one" of the very early Collins made R-390As. It is 
from the '51 order, that actually started to come out in '54.  Roger 
pointed out specific items that these have to identify them.

NO holes in the IF Deck coils, and NO holes or trimmers on.in the filter 
can.  I can tell you that I have pulled BBODs from this beast from day one!

The years later made R-390As, i.e., '67 EAC, didn't have a single one 
they were all Aerovox, yellow "wrapper", resin sealed capacitors.

The only problem with it was THE nasty acid type capacitor on the AF 
Deck board.

However, I'm like you.  I don't really have a lot of faith with some of 
the "other" suppliers.

The Stewart Warner, Collins, and EAC ones are "probably" the cream of 
the crop.  (Simply IMHO.)

Bob - N0DGN

On 4/5/2011 12:14 PM, Tisha Hayes wrote:
>> You obviously have the only known example from the infamous Helena
> Rubenstein collection.  Congratulations!
>
> Is there a modicum of truth that some of the one-off manufacturers ended up
> reselling modules from the other prime contractors and that some of those
> were the junker modules that needed significant rehab?
>
> Those low quantity manufacturers may be collectable, based upon the
> nameplate but I do not know if I would want a radio made from the flunkies
> of modules.
>