Tact Switch or button check on MPC 2000xl?

I replaced the faulty tact switches yesterday and they all do the same thing they did before: nothing. I'm getting really impatient with the "one step forward, two back" sequence of events with this unit. Luckily I bought it with a 6 month warranty, I can return it any time before the end of the year and get credit towards another purchase, but I was hoping I could get it going. I've replaced the floppy with a CF reader, successfully, but the F4 key wasn't working. Some of the other tact switches actually started working after a contact cleaner spray. But F4, keypad numbers 5 and 6, actually apparently none of them worked. Is it possible the resistor or whatever the little component is next to these switches went bad? I'm getting near just letting my tech take care of it and dropping another $100 or more just to get it going. I think it is worth the effort, as it is a special edition orange model with glowing pads but it cost me almost $500 and I know I will never be able to get that out of it with the prices dropping lately. Got any ideas? I searched button check and nothing comes up.