[Elecraft] KPA100 Problem

[Mark Flavin]

Well, I wanted to change the bridge diodes in the KPA 100 cause I was getting some wierd readings and hi swr readings so I decided to upgrade it while I had it apart.  I did the whole upgrade and now as soon as I put it in high power, even at only 15 watts, I get PA HOT readings.  I have checked all the parts values twice and did the calibration again including the C6 adjust, the r26 and 27 adjusts and even pulled the finals to make sure they weren't shorted or anything.  Q3 and Q4 seem fine and are not cracked.  The voltages seem to be fine and I readjusted R6 bias as per book.  Whats wierd is as soon as I hit the key, even at 15 watts the fan comes on with the keying.  A dot gives a short fan wiggle and an dash gives a loneger fan activation.  Eventually it comes on and then I get the PA HOT.  The fan even responds to my voice on SSB.  I mean it comes on almost instantly.  I have checked the archives and am starting to suspect the finals.  I put on new pads on the transistors and checked it all twice.  Resoldered all connections.  All works fine at 10 watts.  Im sure Im missing something but I dont seem to be able to find it.  Any ideas where I can check before I order new finals and go through that work again.  Thanks  MarkN5MF