Physical location of control board on an Onan 5500

Try under the bench seats around the table, near the heater.

Call Onan and tell them the Inverter Board is bad. If you're not producing AC Power, have them send you a new board or warranty the entire genset. It's unusual for Onan products to go out like that, but not unlikely that this is the source of the problem.

Typically, the DC motor outputs at 12 volts, so the leads going in to the inverter are only going to be a ground and a positive lead. Should be very simple to replace. Worst case scenario is you can hook an external inverter up to the DC leads on the front of that generator. Might not get the full 5.5kw from the system, but you'll be able to produce some power.

take the end cover of the generator alternator, and you will see the brush block assembley where it touches the rotor slip rings, clean the rings while you have it open

Its not recommended unless you know how to regulate the voltage and speed of the engine to avoid serious damage or injury (i wouldnt do it)

Because it wont start does not indicate a control board problem It will start but it will shut down within a few seconds if it was. enail me and i will try to help you with the problem [email protected]

Try dinosaur electronics for a cheaper board,
http://www.dinosaurelectronics.com/Onan_boards.htm

What is the problem?

I have searched but cannot actually find what type male of battery it uses, other than it is a Lead Acid Battery. Now with lead Acid batteries, it is the actual Capacity, in Both Amperage output, and Physical capacity. So based upon that ANY 12 V DC Wet Cell battery of the SAME Physical size, and CURRENT capacity will work. Look on the actual battery itself, it WILL/Should have identifying marks written on it. Get one the same, it is NOT all that critical.

http://www.cumminsonan.com/locator The A1 controller is likely suspect.

Take and locate the oil pressure switch and try bypassing it,if that aint it check fuel filter and pump.