[Elecraft] Help with KPA 100 Alignment and Installation

Les and Lynn lynnandles at earthlink.net
Sun Mar 25 21:09:10 EST 2007


Folks,

I solved the problem with the SWR Bridge null adjustment (CI) by reflowing a bunch of solder joints (i.e., Don's usual suggestion) around T1, R21 and R22. 

However, now I have a new problem -  I am drawing to much power in the transmit tests of on pg 50 of the KPA 100 manual. My metered Astron switching power supply shows 25 Amps on key down (2-3 sec.) at 100 watts. Calculating the amperage across R7 shows 21 Amps - still to much. Q1 seems to get preferencially hot compared to Q2 during the 2-3 sec.key down. The signal sounds great in a remote receiver. Changing the values of R26 and R27 doesn't seem to effect the power reading.

I probed voltages and the deviating voltages are shown below:

Q1 RX - All OK
Q! TX - B=0.532V and C= 13.26 V  Note - Voltage input at  K2 Display is 14.2 VDC 

Q2 RX - All OK
Q2 TX - B=0.523 V and C= 13.28 V

Q3 RX - All OK
Q3 TX - B= 0.543 V

Q4 RX - All OK
Q4 TX - C=14.23 V

Q5 RX - All OK
Q5 TX - B = 2.8 V and C=0 V

Any ideas on what to do next would be appreciated.

73,

Les WA3SGZ



More information about the Elecraft mailing list