[TenTec] Paragon Power Supply

[Jim Mitchell]

----------
> From:  ALLEN   SMITH <JKXM17A@prodigy.com>

> All those who said it was probably the power supply were correct.  I
> connected my Astron 35 amp supply, which was already wired up with the
same
> type of power connector for my trusty old Corsair, to the Paragon and now
> it seems to work ok.
> 
> So, that little mystery is solved and now I have a partially dead Ten Tec
> Model 961 power supply to mull over.  Heck of a thing to happen on my
> birthday, what?
> 
> Best regards to all,
> 
> Allen - N0VA

 Allen -

I don't know if this will help you, but I had much the 
same problem with my 961 supply -except it died a 
slow & agonizing death - simply would croak on any
output over 10 Watts or so.

Went inside & wasted much time looking at the clamping
& current protection circuit, which turned out to be just fine.
The gremlin was the large electrolytic filter cap which over the 
years had worked loose from the copper traces on the PC board,
and was arcing over.

This is an unfortunately common problem with large devices that
are simply bolted to a PC board, eventually the board deforms, and
the mechanical contact becomes loose making for a high-resistance
junction.

I pulled the electrolytic off, soldered two soft-steel flat washers to the
traces and coated them with 'Circuit Works' conductive paste. This fix 
has worked well for some time.

While you are in the PS, it's also a good time to add some ferrite beads
to the output leads (RF suppression) and also consider by-passing the
electrolytic with a smaller value (like 100 MFd) 50V non-polarized cap.

The smaller cap will supply current much faster than the larger value
one, which appears to make the keying waveform a little crisper
on my scope.

gud luck 

Jim Mitchell (KJ7QT)

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