K3 repair LPA board #lpa


Robert W5AJ
 

Summary of recent repair of LPA board
THANKS to Keith of Elecraft & Chet N8RA

Don't get in a hurry! 
Replacement on Q2 was a bust, wasn't needed
Doing the 200ma adjustment revealed issue was likely with Q5
This was my first time doing the 200ma adjustment, easier than I'd thought. 
Removing the 100W board required removing three screws and disconnect two wires to circuit breaker, easy.
In the 200ma adjustment, the original Q5 didn't start to draw current until variable resistor was almost fully CW, then quickly ramped up 
Q5 was replaced, 200ma adjustment repeated and rig is performing great now on six meter output! 

On 200ma adjustment, not all emails of the procedure mention, push "TEST" and the rig will produce no RF during the adjustment.
On my K3, Marked three variable resistors on LPA with black Sharpie and the position of resistors is about same place as found (Close or right on) 
I also use higher power reading glasses when working on PCBs, makes for clear view of soldering.
Thanks Keith for timely reminder to attach FET to standoff so it's flat before soldering, keep FET FLAT so has good contact with case.
GL
73 Robert W5AJ