I bought this amplifier with a few other pieces of Marantz equipment (two tape decks and a tuner). It works but there is crackle in the controls, and when I measured the DC offset the left channel has 250+ mv which is bad. The right channel is about 25 mv, so not all that great either. In addition, one of the speaker wire clamps is stuck open, and someone jammed a rather large finishing nail into it as a terminal to wrap the wire around. Idiots!
I should point out here that my soldering skills are minimal at best, and everything I know about amplifiers so far has been gleaned from the Audiokarma forums.
When I got the amp, it had been sitting in a shed for who knows how long and was so dirty inside that there was no component color. It was just a uniform furry gray layer. I vacuumed out the big chunks and blew it clean(er) with compressed air.
I am able to see a few failing capacitors just on visual inspection...the plastic covers on a few have shrunk, meaning they are getting too hot. So the first thing I am going to do is replace all the electrolytic capacitors, and then reevaluate. I've purchased the manual from Stereomanuals.com and next I will make a list of needed capacitors and find a source.