KIO2 Malfunction

Posted by KT4G on Dec 24, 2009; 3:25pm
URL: http://elecraft.85.s1.nabble.com/KIO2-Malfunction-tp4213518.html

Hello all,

I'm having problems with my KIO2.  The unit was functioning normally until recently, then suddenly failed to connect to my PC.

I pulled the unit, set the rig to the settings recommended in the manual, and measured the following voltages:

U1: All voltages within normal range EXCEPT:
Pin 5   -0.03 (-8.0 is normal)
Pin 8   -3.4 (-9.0 is normal)

J1: All voltages within normal range EXCEPT:
Pin 2   -0.02 (-8.0 is normal)
Pin 4   6.0 (4.5 is normal)

J2: All voltages within normal range EXCEPT:
Pin 7   6.0 (4.5 is normal)

Diodes:
D1A   -3.3 (-9.0 is normal)
D1C   0.0 (0.1 is normal)
D2A   -3.3 (-4.0 is normal)
D2C   -1.9 (0.1 is normal)
D2A   -1.9 (-4.0 is normal)
D2C   0.0 (0.0 is normal)

Oscillator is normal.

I highly suspect U1 (MAX1406) is the culprit, since I'm getting the proper voltages from U2 and Q1.  I just want to make sure that it failed on its own and not due to the failure of another component.  Is there somebody out there who could possibly shed some more light on the issue before I risk smoking another '1406?

BTW, I'm running the KIO2 through a USB-RS232 converter.

Thanks in advance,
Larry KT4G (K2 4431)