Last night I picked up an old Rogue GS-100R Solid state amp. I was told it was not working, so I took it home and took a look at it. Turns out, all that was wrong with it was a spring in the reverb unit was disconnected and the solder joints on one of the inputs were broke. Easy fix, I reattached the spring and soldered the input back on and it worked fine. A friend and I played guitar on the amp for a few minutes and then I put it back together. Once I turned it on when it was together, the fuse blew. So then I took the amp back apart, made sure there wasn't a leftover screw somewhere inside the amp causing the short, but I found nothing. I replaced the fuse and had the amp set up exactly how I did a few minutes ago when it was working and the fuse blew again. Any idea what could be causing this?