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Re: [TenTec] Ten Tec Pegasus

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] Ten Tec Pegasus
From: Stuart Rohre <rohre@arlut.utexas.edu>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Wed, 17 Jun 2009 19:13:07 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
Yes, I agree with Ron.  The uncertainty of lightning damage is that they 
could repair the obvious failures and something like an IC bond, or 
transistor gate, could punch the rest of the way thru in normal use 
before a repair warranty expired and it would not be something the Ten 
Tec staff had any inkling was also damaged, because it could marginally 
be good indefinitely.

We had a  Yaesu 5100 dual bander at our club station that took a 
lightning side-surge.  It evaporated a spot on the negative voltage part 
of the circuit board, such that the DC negative was isolated from the 
rest of the rig.  But, the antenna ground was bonded to DC power ground 
and would allow the rig to work.  That was easy to spot as something to 
fix.  But, some 2 years after the original lightning, we had all audio 
output on receive fail.  Naturally we tested output caps, speaker, etc., 
since we could see audio moving the S meter.  All were good.  Then, upon 
closer inspection, there was ANOTHER fine trace from a daughter board to 
main board that carried audio to the external speaker / phones jack, and 
it had opened up.  Probably had been only holding by a thread of copper 
for two years, then fatigue failure got it the rest of the way to an 
open circuit.  A piece of wire wrap wire was soldered in place and the 
radio works, until something else may show up.  We hope that this was 
the last of the ground traces damaged, and we think the path into the 
radio was via antenna ground to power ground trace back out to a ground 
wire on the DC supply minus side.  (an example of a ground loop).

Most ham repair shops will not undertake to repair and warranty a 
lightning damaged radio.  Unplug them from antennas when your station is 
not in use!

-Stuart Rohre

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