Vintage Synth Repair

I second Roy's opinion below.  I'm yet to see an actual failure in one
of the big elecrolytics in these particular units.  The ones made in
china and the US tend to be weaker over time it seems than ones made
in Japan or Italy though overall.  Eg. almost all old Mallories in
60's Fender amps need changing and many from the 70's.  The caps in
old Roland stuff though or old Crumar stuff...still chugging away just
fine usually.  I worked over a Hammond from mid 70's recently, that
rare synth 102100.  The caps all were a little over spec on the ESR
meter on that one.  And it's pretty noisy and I still need to see if
it's that or something else.  But anyway just a few hints for those
interested.  Don't waste your time shotgunning caps from those makers
in particular and not the ones used in ARP.  Only the Tantalums are
highly suspect and usually are best just replaced without asking
questions.  -Bob

--- In vintagesynthrepair@yahoogroups.com, "Roy J. Tellason"
<rtellason@...> wrote:
>
> On Tuesday 18 November 2008 20:33, jeffbmoore_2000 wrote:
> > Hi,
> > I would like to replace the aluminum electrolytic capacitors on the
> > power supply board of my white face MkI ARP Odyssey. The service
manual
> > calls for 250uf 50V, but the synth currently has 150uf 50V caps (blue
> > Spragues). Any suggestions on which caps to use?
> > Also - any thoughts on whether to use tantalums to replace the old
> > tantalums, or to use aluminum electrolytics instead? Cost isn't really
> > an issue.
> > Thanks in advance!
> > Jeff
> 
> Are you changing these out because they _need_ to be changed?  Or
just because 
> they're old caps?
> 
> I'm firmly of the opinion that most of the caps that get changed in
old stuff 
> like this probably don't need to be.
> 
> -- 
> Member of the toughest, meanest, deadliest, most unrelenting -- and
> ablest -- form of life in this section of space,  a critter that can
> be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet
Masters"
> -
> Information is more dangerous than cannon to a society ruled by
lies. --James 
> M Dakin
>