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.