[Elecraft] Beware!

[W2AGN]

Well, I ordered a new MCU on the elecraft web page. Sure hope I can get it in 
time to install for FD!

Now, I checked to see what I did. I was running the K2 off a 12V supply. As I 
planned to use the laptop in FD, I connected it to the same 12V supply. I use 
a Radio Shack voltage adapter to up the 12V to 20V for the laptop. That was 
the problem!

Everthing was OK until I connected the serial cable. Then sparks and the 
computer shut down, and the K2 locked up. It seems that the negative lead 
coming out of the RS adapter is at +12V to the negative input to the adapter. 
So when I connected  the serial cable, it grounded this potential, causing 
problems. It would work OK if they were on 2 separate batteries isolated from 
each other, but the RS DC Adapter is bad news anyway, with that so called 
negative output being so far above ground.

Again, hope I can get a new MCU in time, (nag, nag)

-- 
   _    _    _    _    _
  / \  / \  / \  / \  / \  John L. Sielke w2agn@w2agn.net
 ( W )( 2 )( A )( G )( N ) http://www.w2agn.net
  \_/  \_/  \_/  \_/  \_/  NJ-QRP #57 QRP-L #884 QRP-ARCI ARQrp #86
 EX-N4JS, W4MPC, W7JEF, K3HLU G-QRP #9544  NorCal CQC AKQRP QCWA  FISTS #2781
 SOC, ARLHS, OOTC, Zombie #576  Elecraft K2 #0023 K1 #146, 1151