PS/2 Model 50 help wanted

I have one of these PS2/M50Z. Nice boxen! There wer two versions the M50 and the M50Z. The latter was the faster 286 of the two. <1) The machine contains what I assume to be the hard disc controller, what <capacity/type of drives will the machine accept - and where can I get one? The two standard controllers were 20mb or 60mb but there were later ones to I think 120mb. <2) Can the machine accept 2.88Mb drives (this one is purely out of interest Not that I know of. <3) There is an expansion card with no markings on installed in the slot <farthest away from the PSU. It is connected to what appears to be the <processor socket ('286 right?) by a section of flexible PCB. Likely a memory expansion. <4) The "paddle" on the power switch has been broken off. Can I get a <replacement switch or do I need to get a new PSU? best source is a PS/2 wreck (most any of the older models.). there is a web site that has PS/2 info. Can't seem to find it right now. Allison