I picked up an AC powered RA-1 on Audiogon which was rated a 9/10. The pictures looked ok and there was no mention that the unit had been altered. I received the amp and it wasn't packed properly so the AC adapter prongs left some gouges on the face of the amp. Upon inspecting the amp, I noticed some duct tape sticking out of the bottom plate which was loose and secured with non factory screws. I knew something was up... Instead of dealing with a shady seller who swore up and down the amp was working and in good shape, I decided to rebuild the amp.