[Elecraft] K1 problem

[Chuck Blair]

Folks,
    Have K1 #1239 together up to the xmit align and test (pg. 46) and =
have ran into a problem. The voltage at J7 is 0.0V, U9 pin 3 is only =
0.15 V, and the output at U6 is 0.33V. Everything else is as listed in =
the manual. I have triple checked all connections and resistances around =
the buffer area as shown on the schematic. I thought maybe Q14 was stuck =
on, so I removed it from the board. Still get the same voltage readings. =
C51 seems good (a little over 4V at the mixer side). I am beginning to =
suspect U9 has a problem. Where else could the current through RP4 3-4 =
be coming from? BTW, the spec sheet for an LT1252 calls for a max 12V =
supply, and I get 13+V which is O.K. according to the K1 manual (using =
13.8 supply).
    Spent quite some time looking for shorts, etc. around the U9 area, =
and made sure all the previous tests were good. RX was O.K., at least =
before I pulled Q14. Is it time to replace U9?
Chuck, AC8PN


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