[TenTec] Heatsinking and fans....was: Pegasus - horizontal operation?

[Dr. Gerald N. Johnson, P.E.]

Robert & Linda McGraw wrote:
> 
> I've used the Paragon and my Omni on extensive RTTY contests without
> failure of the radio.  Yep, the radio does get hotter than I'm
> comfortable with.  However, during one evening of hot RTTY activity, the
> power supply lost a bridge rectifier.  It was mounted on the bottom
> panel of the PSU and did not have thermal compound between the bridge
> device and bottom panel.  I replaced the bridge device and added a
> liberal amount of white thermal compound.  No problems since.
> 
<SNIP>

Liberal amount of thermal compound is as bad as NO thermal compound,
often worse. The thermal compound is a better heat conductor than air,
but not as metal. There should only be enough thermal compound applied
to fill in the irregularities of the surfaces of the
rectifier/transistor and heat sink, but not so much that it separates
the metal where metal already touched. It doesn't flow well enough and
the parts aren't strong enough to push it all out. Just needs a thin
film, not a blob.

73, Jerry, K0CQ

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