[Elecraft] K2 PA and 232 problem

[Bob G3PJT]

Hi Don
I was just about to send something to the reflector. Both the 1406 and 
the 5146 had failed but I do not know why.
However the solution was :-
- find out which chip was crowbarring the 5v line. Pull the PIC - it was 
OK in my case. Cut  pin 16 on the 1406, check and resolder if OK (it was 
OK in my case) Do the same with pin 7 of the EL5146 which showed that it 
was that chip which had failed. Extract the 5146 by cutting the pins and 
clean up the board with desoldering tape. Sacrifice the chip not the 
PCB. Replace with a 8 pin socket as EL5146 is discontinued here. Use 
almost any op amp with the same pinout except for pin 8 and clip off pin 8.
- I determined which channels of the 1406 were not working using a 
prototype board type interface and then rewired the 1406 to use the 
unused 232/TTL interfaces, only the pin5/12 circuit had failed in my case
- replace the 78L05 as its not clear how much abuse it had suffered.

73 Bob G3PJT