I am interested in recapping a Heath SB401 and a SB301 but I have several
questions.
1 Do you try to desolder each old cap or do you simple cut out the old ones
and add the new ones?
2. Where is a good place, web or otherwise to purchase new caps?
3. I been told that if the electrolytic are to old they will not polarize
correctly. So how do you know?
Thanks for any and all replies.

Jump'n Jack Flash wrote:
I am interested in recapping a Heath SB401 and a SB301 but I have several
questions.
1 Do you try to desolder each old cap or do you simple cut out the old ones
and add the new ones?
2. Where is a good place, web or otherwise to purchase new caps?
3. I been told that if the electrolytic are to old they will not polarize
correctly. So how do you know?
Thanks for any and all replies.

cap etc replacement - it depends on how "well" the original was put in
there....if its been done "properly" then the wires will have been
mechanically twisted round the terminals, with the solder providing the
final "electrical connection only" finishing touch . This IS the
correct method of doing it in manufacturing - provides protection
against mechanical shock loosening leads, as solder has almost NIL
mechanical strength.

If, like most exeprienced home brewers, the builder realised that the
caps etc would eventually have to be replaced, then the leads would
have been poked throught the tag and not twisted - in this case,
removal is easy - just heat and pull on the lead.

Have a look - if its method one, then, from a service point of view,
cut off the old leads and solder on top of them. Too much risk of
damage to the support structure if you try to untwist/desolder a lead.
The restoration purists will have hysterics on this, but as a service
technician concerned with getting the job done with no additional
damage, its what I would reccomend.

If it hasnt been fired up for a long time, a good service tip is to
connect a 100w light bulb in series with the mains input to the radio -
this will current limit it enough to prevent violent destruction and
give the caps a chance to "reform' - but it is FAR better to just
replace ALL the electrolytics anyway, chances are they will have dried
out and lost value....

Most high value resistors ( 100K) will have drifted UP in value - this
is sometimes a subtle fault and can cause many weird symptoms,
typically loss of sensitivity - radio just doesnt "feel" right....the
beauty of valve equipment is you can pull the valves from their sockets
to isolate them out of circuit to measure them...

Replacement caps - sorry, cant help you there as I am in VK. But it
should be easy enough to find with Google.....

Andrew VK3BFA.

I agree with the VK3. The conditions he relates are the ones you'll
encounter. I'll add to the fray that when there are several leads going
to, for example, a tube socket pin on an old set, its just too much to
ask to clean everything out to make room for the new component. Oft
times you'll create more problems then will be solved. Just be careful
and be a bit artful when installing the new parts so they'll look good
and work properly. If there is only one lead to worry about, it may
well be appropriate to wick the joint and un-clench the old lead. That
will be a judgment call on your part. As far as where to buy, I can
recommend Mouser. They have the gamut in capacitors, et al, both the
smaller types as well as the larger "orange drop" types. It does
appear, however, that the selection of axial electrolytic caps (1-40ufd
range)at 450v (typically) is getting smaller. I've laid in a stock of
these, of late. I'm sure some of the restoration purists may have
their word in this and that's absolutely appropriate. I re-build gear
to get it (back) on the air, reliably. I don't chose to re-create the
Hallicrafters production line.

Jump'n Jack Flash wrote:
I am interested in recapping a Heath SB401 and a SB301 but I have several
questions.
1 Do you try to desolder each old cap or do you simple cut out the old ones
and add the new ones?
2. Where is a good place, web or otherwise to purchase new caps?
3. I been told that if the electrolytic are to old they will not polarize
correctly. So how do you know?
Thanks for any and all replies.

On Sun, 9 Jul 2006, Jump'n Jack Flash wrote:

I am interested in recapping a Heath SB401 and a SB301 but I have several
questions.
1 Do you try to desolder each old cap or do you simple cut out the old ones
and add the new ones?
2. Where is a good place, web or otherwise to purchase new caps?
3. I been told that if the electrolytic are to old they will not polarize
correctly. So how do you know?
Thanks for any and all replies.


FYI, FWIW....

This might sound like I am throwing you a "curve ball" but I'd like to ask
if you are doing this because: i) "its cool" or ii) because neither unit
is working and you are sure the problem is an open or shorted or leaky cap
and you are sure that replacing all of them will bring both units back to
life?

There is a philosophy, which is good, that doing a recap job will surely
make it unnecessary for the next 50 years to recap anything again....

Then there is a philosophy, which is also good, that "don't fix anything
that ain't broken". And, if something is broken, then fix just that (I've
had a lot of dentists urge me to "fix" something that was not broken but
they said could break any day, and I've had those somethings for 30 years)

Then there is a philosophy involving preventive maintenance (this is real
good for flashlights with replaceable batteries, oil changes for cars,
blood tests in the doctor's office, etc, etc.).

I usually go by the second philosophy, but not because I can prove its
better. Its just "my" strategy and approach to life.

Just FYI, FWIW.

"Jump'n Jack Flash" wrote in message
ink.net...
I am interested in recapping a Heath SB401 and a SB301 but I have several
questions.
1 Do you try to desolder each old cap or do you simple cut out the old
ones and add the new ones?
2. Where is a good place, web or otherwise to purchase new caps?
3. I been told that if the electrolytic are to old they will not polarize
correctly. So how do you know?
Thanks for any and all replies.
IF you are not allergic to reading -- some great web sites for further
education

Tim Reese - Charlestown Navy Yard - Boston, MA
http://www.nmr.mgh.harvard.edu/~reese/electrolytics/

Philip I. Nelson
http://antiqueradio.org/recap.htm

Just radios
http://www.justradios.com/captips.html

Need "Smithsonian or museum quality" restoration tips
http://www.earlytelevision.org/cap_replace.html
http://www.earlytelevision.org/electrolytic.html

CDE / Mallory - South Carolina
Capacitors of almost every kind
http://www.cde.com/

Also sounds like you need to become acquainted with large mail-order
electronic parts suppliers -- all have Internet (and paper) catalogs) as
well as on-line Internet ordering.

Mouser
MCM / Newark / InOne
DigiKey
Allied

gb