8 Oct
2010
8 Oct
'10
6:59 p.m.
On 10/08/2010 08:52 PM, Eric Smith wrote:
Richard wrote:
New capacitors are not "more reliable" than the old until infant
mortality is accounted for.
Also newer parts may exhibit lower ESR than originals did when new with
undesired side effects.
the two major failures of electrolytic capacitors are shorted, open
(usually dried out). The
former is easy to spot. The latter is also easy as the capacitance will
be low and they
don't form up and there may be evidence of the pressure plug blown or
residues indicating
leakage The third problem high ESR is also easily checked and weeded out.
Life is easier as most of the systems of that generation were linear
types and likely had
generous margins.
Myself I'd not have worried the caps near as much as the transistors
used. Some parts then had
terrible spec drift over time (germanium).
My experience with HV supplies and tube radios/transceivers in the same
era is if the caps form
they are good. However, resistors used then were not as stable, and
some of the caps used for
lower values in the .001 to 1uf range were far more suspect.
Allison
However, this all seems like a huge PITA compared
to just replacing
the capacitors.
Yes, replacing capacitors is generally easy than reforming them.
The
main reasons to reform them instead are:
1) If you're trying to preserve an historical artifact
2) If you can't easily or inexpensively get a replacement with
comparable specifications.