[Heathkit] Power supply parts for SB-200

[Jim Shorney]

This is something that I've not seen addressed very often, but I've
always wondered about it. Why would one NOT use 105C electrolytics in
any type of repair in any equipment that generates heat? They aren't
that much more expensive, and in my experience, generally are of better
quality and hold up longer than 85C units. I've used 105C units in
monitors, stereo gear, vintage AND sand-state ham gear, power supplies
(switch mode and linear), etc., and never regretted it. I've also had
gear that I've had to throw 85C units at every year or two to keep
running, until I discovered 105C units (yeah, I know, poor design). I
also see cap rebuilders on various reflectors proudly publishing photos
of thier creations using 85C caps, and have always resisted saying
anything thinking it wouldn't do any good anyway.

You have to remember, the temperature inside the equipment in question
isn't the only factor; the caps also generate heat _internally_ in
operation. This is often an easy way to diagnose bad caps in switch
mode power supplies and computer monitors - if they feel real hot*,
replace them. The better a cap is able to tolerate this internal heat,
the longer it will last. 

*After removing power, of course. The can of the cap CAN be hot
electrically!

No offense meant to Glen, but I agree; use the 105C caps.


On Mon, 21 Nov 2005 22:25:01 -0500, km1h wrote:

>Obviously you dont understand electrolytics, their temperate specifications 
>nor other rating data.
>The original Nichicons and others used by Heath are so far superior to the 
>ones you mentioned it is not even close.

<snip>

> That would certainly not be my choice of capacitor for
> a HV doubler supply. First of all the ripple spec is
> far from good, the load life is low and the
> temperature rating is only 85C. Now for many hams the
> mantra is "Cheap Is Best" but this is not the time to
> count pennies.

> However I suggest the 105C Cornell Dublier 381LX
> series which is designed for switching supplies and is
> a superb cap for amp use. Ive been using that series
> since they came out for all my amp needs.


-- 
Jim Shorney      -->.<--Put complaints in this box
jshorney (at) inebraska.com
Ham Radio NU0C
Lincoln, NE, USA
EN10ps
http://incolor.inetnebr.com/jshorney/