$200 is a heck of a price for a functioning ST-400, especially with meters. I'd guess about $50 or $60 for meter service, if removed from unit. The unit always got good reviews and thought it sounded pretty good. Mine was very reliable and quite the work horse, except the output transistors tended to go over time, especially when loaded with low impedance modern speakers. I went through this a couple times and no job for amatures, as you need to tear a lot apart to get at them. I later converted the output to the beefier 16 transistor set up used in the newer 416. Talk about a job. Not going through that again.