Onan Genset Blues

Fault Code 41 :  There is no way my hands will be clean for days - have just removed the control board on our Onan MDK-AU genset, which took about 4 hours.  Tomorrow I'll put it back again, after cleaning, in the vain hope that it might work.

This is very frustrating - the generator runs perfectly, when the controller will let it.  But an intermittent fault in the control board now prevents it from starting, most of the time. The controller reports that the rotor (field) is grounded (fault code 41),  however when we test the field circuit it is not grounded.  So the control board is faulty.  We've heard of similar problems with Onan control boards, but even knowing we're not the first, its still VERY frustrating.

A phone call to Onan back in Australia revealed that a new control board would set us back $2700.00.  Yikes. 
If anyone has any clues on this issue we'd be pleased to hear from them !  We hear that our friends on SV Sea Bunny and SV Tweed are also working on their generators, so we're not the only ones nashing our teeth.