Borked or Broken: framing nail gun

Donating my somewhat functional Paslode cordless framing gun to the cause. I’m hoping it’s an easy fix. I suspect it may be a battery problem, damaged/dirty contacts, or a faulty wire.

I’ve tried two fully charged batteries: one new and one old. The gun will fire one or two times then stops. The indicator light goes from blinking green to solid red which according to the manual means a flat battery. So it could just need a new battery (but doubtful as two fully charged batteries didn’t work). The reason I still think it’s a power issue is the fan is running slower than normal. Tried to clean the battery contacts, and gave the fan, combustion chamber and firing head a good clean out but no go. If new battery doesn’t work next step would be to pull it apart and check for any loose or damaged wires, and test if it’s sparking properly.
I don’t really have the time (or brain power) to try and fix it right now so anyone else is welcome to try. Otherwise I’ll have another go when I get a break in my house building.

Made a good effort to fix this but 3 separate opinions say its dead. RIP. Thread closed.
On a side note, I did fix one of the electric planers in the woodshop.