[R-390] capacitor analysis

John Saeger [email protected]
Mon, 3 Jun 2002 10:41:20 -0700


Walter Wilson wrote:
>
> I guess I don't understand what the big deal is.  You can replace every
> paper capacitor in the R-390A plus the tantalum for about $30 or so.  And
> when you replace them all, you're going to invest many hours doing the
> replacements.  If you are going to all the trouble to replace them, why
> worry about saving $15.
>
> Below are a few items from others that have been posted to this list
> previously.  I hope this helps you make your decision.  Just be careful
not
> to redesign the radio too much. [;-)

O.K.  This makes a lot of sense.  I shouldn't worry about cost so much.
I'll probably go with the OD's almost everywhere for their *proven
reliability*.  What still concerns me is C501, a 5000pf ceramic which is
smack dab in the middle of the IF signal path.  It's a shame to put
something as nice as an orange drop at C553, when we have a cheapass ceramic
right in front of it.  Should I also replace C501 with an orange drop?  Or
since cost is no object, should I consider replacing both C501 and C553 with
mica's (available from Mouser) which have dissapation factors that are at
least an order of magnitude lower than even the mighty orange drop?

Thanks,  John