[SignalOne] MilSpec 1030 repairs

[Jim Garland]

Congrats, Bob, nice bit of sleuthing.  My buddy Jerry K8RA has been going
through the same sorts of problems with a newly acquired CX-11A. He's
pulling his hair out over the inadequate documentation.
73,
Jim W8ZR

> -----Original Message-----
> From: signalone-bounces at mailman.qth.net
[mailto:signalone-bounces at mailman.qth.net]
> On Behalf Of Bob Sullivan
> Sent: Wednesday, March 10, 2010 5:46 PM
> To: signalone at mailman.qth.net
> Subject: [SignalOne] MilSpec 1030 repairs
> 
> 
> 
> This list is for discussions regarding collecting, repair, use and sale of
Signal/One radios
> and accessories.
> 
> Documentation on Signal/One radios can be found at
http://www.hamanuals.com and
> several other sites on the Web.
> 
> .
> Listmates,
> 
> Since there have not been too many posts lately I thought I would describe
troubleshooting
> efforts with my MilSpec1030 which I generally use daily. It's my all time
favorite
> transceiver! During a recent RTTY contest the transmitter suddenly quit
along with that
> "familiar" burning smell!
> 
> After removing the final amp/driver board and heatsink assembly I noted
that one of the
> MRF421base resistors (10-ohm) was burned up. Hmmm 
 what caused that?
Further
> investigation showed that one of the tabs on one of the MRF421's had never
been soldered!
> (Sig/one QC practices?). Apparently it has been making contact and lots of
heat due to
> RTTY ops caused it to open. I replaced both MRF421's with MRF422's. Tested
but still no
> output. Found there was no RF drive.
> 
> Finally found that there was no T/R voltage on transmit. Checking the
power supply board I
> (finally) noted that the RED LED (CR12) was not lighting on transmit (like
it should). More
> troubleshooting found Q12 (2N2907) defective. Thankfully this transistor
was socketed.
> This failure seems unrelated to the original problem but replacing Q12
corrected the T/R
> issue. RF drive now okay and output power back to normal.
> 
> These rigs are pretty but NOT easy to work on. This is not helped by the
numerous manual
> errors. I wish S/1 had spent more time making sure the documentation was
correct rather
> than gluing all those little photos at the beginning of each section! Hi.
> 
> 73, Bob
> WØYVA
> http://www.isquare.com/personal_pages/ras-hardware.htm
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