[Elecraft] K2 Finals - Chronic Blow-Outs

[R Thompson]

   When I read this today it reminded me of a problem that I had with my
TenTec 6M transverter.   Sometime after TenTec ceased production of that
kit, they did another run of them.  I picked up one from the last
production run, and it performed as advertised.  Then out of nowhere the
finals failed for no understandable reason.  After taking a close look
at what remained of the factory supplied finals, 2SC1969's, and checking
it out on the internet, I now think the kit came with bogus (fake) final
transistors.

   I wouldn't begin to suggest this if you hadn't said that it appears
that the finals were replaced before you got the radio.

   Here is a link I found on the subject:

http://www.4hamradio.com/counterfeit-mitsubishi-2sc19692sc2312-transistor-test/

   Eventually I did find some, well I think they're close enough to the
real thing, they work and they take a lot less drive than the old ones
did to get the desired output.  I would strongly suggest, if you're not
already doing this, that you get replacements from Elecraft and not off
of an auction site.

          Ron VE8RT

On Sat, 2012-10-13 at 06:08 -0700, w7asa wrote:
> Man!  You guys are really encouraging-and FAST!
> 
> The K2 has ONLY the SSB option at this time. I am building the ATU, 160,
> 60m, and a few more goodies on my bench as we speak.
> 
> ---
> >>> I bought this on the internet very recently and have basicaly no
> >>> information available from the seller. When I ordered the ATU kit from
> >>> Elecraft, I also ordered two K2PAKIT packs just in case, *figuring that
> >>> I would never need them* 
> 
> I installed all K2PAKIT components, including Q11 & Q13, and the 1.5 Ohm
> resistor R50. My bench has a grounded ESD mat and wrist strap and I've made
> a career working to IPC610/620 and mil electronics standards. So, I am
> really comfortable inside of this radio.
> 
> The general workmanship on the main board was not very good but I am told
> that it was functioning for years.  After I have it running,  I intend to do
> a lot of flux removal, reflow & rework to clean it up.  However the SSB unit
> *is really excellent*: shiney joints, no voids, great fillets... so I knew
> that it was built by someone else as soon as I saw it. I found paperwork in
> the maual and the EXCELENT SSB board was made by Don Wilhelm!  Great Work
> Don!  Rest assured, I used to do a lot of nit-picky QA & rework for DoD and
> even through my magnifiers, your SSB board is really superb work ! ... 
> small world, eh? (and no, I do not work for Don...)
> 
> Thanks for the settings and reading info. I will do the current, bias
> voltage and settings checks as indicated by you guys and thanks for the
> direction.  I am brand new to the K2. My next two replacement parts kits are
> ETA next week, so I have plenty of time to snoop, measure, poke & prod until
> then, but I'll go straight for the settings - being the low hanging fruit.
> 
> 
> Thank You & I'll keep you posted - 
> 
> 
> 73 de Ray
> W7ASA ..._ ._
> 
> 
> 
> 
> 
> --
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