[MFJ-Ameritron] MFJ-945E problem

[Lu]

When I put this HF/6m tuner inline, I can't hear anything on 10m during a
band opening and the meter shows no output on TX.  When I remove it from the
system, my receive comes back and the radio transmits fine.  I've eliminated
coax switches and coax jumpers as potential problem sources.  It started as
an intermittent problem when it was in the car, but now in the shack it has
stayed faulty, and turning it or shaking it does not bring back correct
operation like it once did (in the car I had to run it upside down to get it
to work right but now even that doesn't help).  I've never run more than
100W through it.  I re-flowed the solder joints on the two SO-239 centers,
but it didn't help.  Visual inspection did not bring out any obvious
problems...could it be a cracked PCB trace?  Is this a problem common to
this model?  Tnx for any help.

Lu