[Elecraft] K2 receiver

[John Chance-Read]

I am trying to find a fault in the receiver (I've lost 3 dB of signal) i.e. 50uV in only give a reading of 6 on the meter.
So far no luck but I've now stripped off the SSB / 100W / 160 m / Dig Filter accessories to make it easier to find.
I've linked W1, W2, and W3 but can some one advise me on other Plug/Sockets that need linking ?  Its a long time ago since I built it and the old brainbox isn't very good on the recall.
John  G4BOU