[Elecraft] KPA-100 Bias Adjustment WITHOUT AN AMMETER

[Tom Hammond NØSS]

Weveral folks recently have commented that they had problems adjusting the 
BIAS on their KPA100 because they didn't trust the current measurement 
capabilities of their test equipment.

Here's a message which was posted to the KPA-100 FIeld Tester's reflector 
while we were busy FTing the pre-release KPA-100. Maybe this will help some 
of you.

WAYNE: If this is no longer a valid method, PLEASE advise a.s.a.p. - Tom N0SS
_____________________

Sam, N5WU wrote to the KPA-100 Field Test group a while back:

   I do not have the luxury of a current meter on my power supply
   and I couldn't get my ammeter working to measure the current
   into the K2/100 so Wayne sent me a suggestion that worked well
   for me. For those of you in the same fix, here is a work around
   that works very well.

   Make sure the power to your K2 is off. Using small clip-on
   leads, clip these to either side of R7. That is the large black
   resistor in the center of the board toward the back of the amp.
   With the leads connected, set you voltmeter for the lowest
   reading you have, at least 1/10 of a mv.

   Set R6 fully CCW. Turn on the K2 and look at the meter. Write
   down the mV reading. It will be very close to 0.0mV or just a
   little more. Mine was at about 0.5mV.

   Go to CW TEST Mode (VERY IMPORTANT TO BE IN "TEST" MODE) and
   press Tune. Now adjust R6 for a meter reading of 2mV greater
   than the receive voltage you just wrote down. Tap any key to
   get out of tune.

   That is all there is to it. My R6 ended up at about the 4 to 5
   o'clock position when viewed from the front of the unit.

   Happy adjusting.....

   Sam
   N5WU