[Elecraft] ALC THR level KPA500

[Herbert Botero]

Hello



My callsign is HK4T and I bought, second hand, an Elecraft KPA500 amplifier
from the series 239 that works with firmare 1.38.

The amplifier works correctly in all its functions except for the ALC THR
level control.

On the display the ALC THR value varies between 0 and 210, however the ALC
output voltage remains constant at -7 V DC

What tests should we carry on to detect and repair the equipment?

I believe the problem is on the LMC6482 components or the zener D37
(diagram No. 2). Does anyone know where those are located?

I am an electronic engineer and I have the equipment and knowledge
necessary to carry out the repair with your collaboration.


Best regards,





HERBERT BOTERO B.

ANTECOL  antecol2 at gmail.com

Tel.(+57) 4411 3952 y  Cel. +57 310 442 2012

Medellín - Colombia