sorry man i really don't understand what u mean. please answer in a full sentence because english isn't my main language but im trying to help.
you can find videos on youtube how to open up your case from the 2500, which will explain you well which screws to take out. losing some cables inside shouldn't be a problem for you. the connectors you can loosen up with a flathead small screwdriver and be careful. on the right control pcbs the cable on the front right corner is either a flat cable with a "clip" to open, just pull the small plastic clip towards you (the front) or it is just a connector without a clip, pull the cable out the same way without opening the clip (bc there is none). desolder the 16 solder joints for the cursor buttons, put new ones in and resolver them. for the sliders, just dismount the pcbs board and desolder the 12 solder joints for the two sliders, put new ones in and resolver them. can't be clearer than that.
E-Mu SP-1200|LOTHAREK, NORITAKE
MPC 3000|VAILIXI, RAM
MPC 2500 SE|JJOSXL, RAM, CD, HDD
MPC 60 MK1|VIMANA, RAM, SCSI
MPC 2000 XL|RAM, CF, 8OUT, EB16