[Boatanchors] replacing PS capacitors

[Mike Clarson]

Dick: I recently did a Swan 117XC supply, and it sounds similar to the ones
you are doing. I replaced the caps, but the ones I had were 200MF instead of
100, so I decided to upgrade the diodes also. 3amp 1000 PIV diodes are
available for like $.12, so it seemed like cheap insurance, especially since
the originals were old "top hat" diodes. Works fine. Look at some of the
Radial lead caps (both leads coming out of one end). Panasonic units in
Digi-Key run $2.00 for small values, like 33MF, and less than $5 for 100MF
units in Panasonic (all 450V). Recommend also keeping heat generating
components (bleeder resistors and transformers etc) away from the filter
caps. Some people recommend increasing the value of bleeders to reduce heat
and size, I would avoid this as sometimes the bleeders also served to help
regulate the supply by reducing the unloaded voltage. Good luck. Mike,
WV2ZOW

-----Original Message-----
From: boatanchors-bounces at mailman.qth.net
[mailto:boatanchors-bounces at mailman.qth.net]On Behalf Of Richard Keller
Sent: Thursday, September 23, 2004 12:08 PM
To: boatanchors at mailman.qth.net
Subject: [Boatanchors] replacing PS capacitors


Ok guys, I need a little bit of advice here. I am putting
new electrolytic caps in two power supplies, one Heath and
one Drake. After all I have read on the list, I assumed it
would be a piece of cake. Not so.

I have searched a stack of catalogs for the caps and found
replacements for most, but some are just not there. I can
sub 22 for 20 and 47 for 40 and 33 for 30 but how much
leeway do we have regarding the capacitance and voltage? I
just cannot find any 125mfd at 450 or 80 at 350. I know you
can use a higher voltage with these aluminum electrolytics
but that is no help with these. I found 100mfd at 450 but
they are 10 bucks apiece. I need 6 of them! What do you
suggest?

By the way, I will not be gutting the cans, but instead will
mount them underneath.
73, Dick KF4NS
St. Petersburg, FL 33714 USA
Keep the glow!