I just got my MC2100 last week. First thing I did was hook a dvd player up to it and fired it up for an hour and let it play in stereo mode through left and right channels. Now later on that night I planned to do and overhaul/inspection replacement and 1/4 jack mod. Lastly will be banana jacks for both left and right 8 and 16 ohm and coms only. The rest will be snipped inside.
First I replaced the original input coupling caps c310,302 which are mylar and swapped them out for Polypropylene .47uf which smoooths out the high end. I replaced c307,308 emitter bypass caps with exact and added a .1uf film bypass cap between poles to clean up any extra garbage on the lines. c309,310 output couplings with exact electrolytic 100uf 15v+.1uf bypass.
C303,304 are the dc power supply caps 470uf 25v replaced with exact +.1uf bypass. All electrolytics should be changed not because of previous use but length of life. C1,2 feedback loop caps 330uf at 3v with a higher voltage +.1uf bypass as well. C11,12 DC voltage gain 150uf at 50v+.1uf bypass. C201,202 are the big cans in the cage 39000uf at40v. Only need replacing if signs of leaks and hum. C203 is a multi cap that measure 80/80/150/50uf at 200v min.
Next I pulled out each heat sink panel(two for each channel and silver thermal pasted the transistor covers 3 on each plate and replaced out the crusty block type resistor with stock. Now the driver cards I did the sentry monitor mod on both and cleaned up some resistors on each that looked burnt at the solder joints plus silver thermal pasted down the transistor cover on each card.
I also installed cooling fans on the top of the cage.