Cummings generator

[charlyiiv]

Hi all,
We have a Cummings Generator onboard with fault code 1, problem is it seems to be linked to a problem which keeps blowing the PCB. Engineers have checked it out and all running as it should so why does the board keep blowing? Suggestions greatly received

 

[jrudge]

Cummings is Onan. Onan code 1 is overheat.

 

[steadyeddy]

Check the revs are not too high i have found if the engine revs are to high they blow the diodes on the pcb check the voltage on a muliti meter