Hey there folks. So I bought a amp used and it was partially dead. I would like to see if I can fix it---if possible. I have a soldering iron and electrical citciut mathematic knowledge. I filed a claim against the person too. I tested it back and forth with a known working speaker and consistent power, my truck. It is a 4 channel. Problem: Only 1 of the 4 RCA inputs works. Actually I should say only 1 input gives sound through the respective out-channel. Like mentioned, I tested it thoroughly. It doesnt blow fuses or give any static that I have noticed. Questions: Common problems that may make that occur? Seeing as the one input that works seems to work perfect, it leaves me thinking it -could- be a more minor problem. Could... I would expect the amplification is done in one 'process' and the power is divied up 4 ways, rather than 4 individual low power amplifier. So thats why I am wondering it if it a minor short or something like. Toasted connection... NOTE: WHen I received it there was something loose inside it. Knowing that metal conducts electricity, lol, I remove the bottom and found two screws. Before I did anything... No visible arcing from a glance at the circuit board. If anyone has iny input it woudl be great. I have a few friends who are senior in electrical engineering so I may pick their brains this weekend. It is presently disassembled on my table.