You May have seen me posting here regarding a 9090db. It appears that it needs a Dolby board renovation. Before I do that , before I jump in the deep end of the pool, I thought I should perhaps try resurrecting my dads 5050. Something presumably a bit easier. LBPete suggested I start a new thread so as not confuse the two works in progress. This is what I know about the 5050 as of now. After powering on, the panel lights come on, the tuner appears to be working. There is no sound, no output. I do not hear or see the relay click. So I think that means it does not come out of protection. At the input to the driver board, I have a good signal on one channel and on the other, the signal is about half and is floating on about -1.5 volts. The good channel has no dc component to it. When I remove the input connector to the driver board, there is zero volts dc on the input pin of the good channel. There is -4volts or so on the input pin of the driver board for the bad channel. There looks to be a good signal on the bases of the final power transistors of the good channel. No real signal on the bases of the final power transistors of the bad channel. I am injecting a 1khz signal onto the aux port and using a scope and DMM for measuring. Any thoughts, guidance would be most appreciated. I am putting together an order to replace the electrolytics. I am hoping to get an idea of what has failed so I can order any other replacement parts along with the electrolytics. I am going to replace the fuse resisters also, although they seem to be ok at this point.