[Elecraft] k2 test rx v.poor

[Chris]

hi im at the stage with k2 sno 6436 where i have done alignment & test part 2
pll,vco,bfo, all tested ok with good ranges. vfo linearization ok, but next
to no audio noise in my headphones on recive (audio side tone good and strong on test)
if i send some v,low rf from my old icom on 40m i can hear it but verry week.rf pre amp
makes it a little better .att kills it. if i have some low  rf at 5.915mhz on a wire and put it neer 
u11 or u12 i can hear the signal verry strong. neer to q22 its week agc, fast/slow/off
has no effect, could this be down to u4 on control board its out put is 7.55v i am
waiting for a new one from elecraft my last 3 k2's worked like a dream i would
be happy to recive any help thanks chris g0wfh