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<DIV>Hi Larry:<BR><BR>I've seen a few failures like this, but not this
bad!!!</DIV>
<DIV> </DIV>
<DIV>Most of the tantalums that Ampex used in the quad era were mil-spec,
hermetically sealed units, and they almost never go bad. However, these
particular ones are wet tantalums which are not hermetically sealed. Since
these are simply filters across the power supply busses, you could replace them
with modern-day electrolytics which are small enough these days to fit
in the space available. However, if you insist on the "original" parts,
they are still available from suppliers like Avnet or Arrow, but you'll pay $40
to $50 EACH for them. I did spot a few on eBay for $15/ea....a real
deal!!!</DIV>
<DIV> </DIV>
<DIV>I have seen some instances where a board was "shotgunned" and all of the
expensive hermetically sealed caps (the ones that almost never fail!!!) were
exchanged for cheap electrolytics. I've never believed in doing that,
because I've experienced more failures with the new electrolytics than
with the old mil-spec caps. But in the case of actually needing to replace
one of the expensive caps, if we don't have the original part, I'll go with an
electrolytic unless the customer requests otherwise.</DIV>
<DIV> </DIV>
<DIV>Don Norwood<BR>Digitrak Communications, Inc.<BR><A
href="http://www.digitrakcom.com">www.digitrakcom.com</A></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=leodham@centurylink.net href="mailto:leodham@centurylink.net">L.E.
Odham</A> </DIV>
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<P>Hi all,</P>
<P> </P>
<P>I had a interesting Saturday afternoon repairing board #12 from one of the
1011 colortecs here.</P>
<P>A couple of the 270 uf mercury electrolytic capacitors had leaked over a
period of time and the electrolyte had dissolved every bit of copper clad it
came into contact with.</P>
<P>It wasn't in a machine at this time, thank goodness. It had
been sitting quietly on the shelf a number of years as a 'spare'???</P>
<P> </P>
<P>An ugly mess indeed....</P>
<P> </P>
<P>photo attached</P>
<P> </P>
<P>Larry Odham</P>
<P> </P>
<P>Quad Tape Transfer</P>
<P><A href="http://www.QUADTAPEXFER.com">www.QUADTAPEXFER.com</A></P>
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