You should be able to look at the schematic on their site and find how its installed. Shouldn't be too big a deal. Be sure and dischrage the caps before you poke around in there. If you talk to Mike at Ameritorn, I think he can walk you thru it. If needed I can take a look in in mine, its a 4 yr old 811H, may have the mod.
73, Dave KD8GEH
Its a simple install. They seemed confident this was the problem. About 1-2 minutes in the conversion, he asked 2 or 3 caps? Soon as i said 2 a 360 and a 500pf, he said theres the problem a 360pf should be in parallel with the 500pf. That will bring your load up to where it needs to be. Sounds good enough, these guys should know the amplifier since they repair them.