[Tech-Assist] Harris SX5A logic problem

[radioranger]

I take care of and curse at a Harris SX5A, that until recently has been
pretty reliable. 

Last weekend, after a 5 inch downpour, the three towers in the swamp took
water up past the base insulators.  According to the Burk logs, the
transmitter faulted but didn't shut down, then continued to burp and fart
for at least a couple of hours until I happened to listen and turned it off.

I got to the site, brought the transmitter up at 500 watts without any
overloads and noted that the common point had shifted from 50 j0 to
something like 70 -j something, so I shut it off till the water receded.  

This morning I found the water level below the base insulators, so I
attempted to fire up the SX5A with no luck---all I got were PA current
overloads.  Same results into a dummy load.

After replacing 4 FETs on the PDM boards and 2 RF FETS it still isn't
working--- the odd thing is that the PA current meter is reading downscale
whenever you try to turn the rig on, and that meter stays pinned downscale
until I turn off the control power breaker.  In desperation I finally
disconnected the PA and power supply current samples and the PA voltage
sample and got the transmitter to come on at 500 watts with OK audio, but
when I scroll through the multimeter readings some of them are showing
negative numbers.  I swapped around some of the logic multiplexer chips with
no good results, and am headed back tomorrow to go round two with the beast.
Do any of you SX5 wizards have any ideas about what I'm missing?

Steve Brown
Radio Rangers
Minneapolis