[Yaesu] HI SWR problem - Mark V

[James Hall]

Gentlemen:

I need help.  My (second) Mark V has quit transmitting with HI SWR 
readings on all bands - and into a dummy load.  This is similar to what 
occurred with my first Mark V.  That rig was replaced by Yaesu after it 
went down for the fourth time.  I remember at the time, Andy, at Yaesu, 
was suspicious of static build-up (DC currents) on the antenna coax 
causing, ultimately, the diode breakdown.  Now, I have checked and 
re-checked the voltages on my coax and have consistently measured 0.0 
volts.  The ground system is sound and I have had no problems like this 
with the other rigs in the shack - FT-847, Elecraft K2/100, Drake 
R4B/T4XB, and VHF/UHF rigs.

I AM VERY FRUSTRATED.  I am throwing this out to the group - besides 
the need to send this rig to Yaesu for what I know are diode failures, 
is there ANYTHING that I can check, replace, or do to keep this from 
happening again ???  I plan on jerking the coax out that is specific to 
this rig hoping on hope that it's this simple.  Again I have left my 
Fluke DMM across this coax for hours - and have tried to provoke it - 
but nothing but 0.0 volts.

Any help would greatly appreciated.

James C. Hall
WB4YDL