so, I came to find one day, that, my RP250 would randomly switch presets, and that one of the buttons didnt snap back up when depressed, and, if i shook the unit, something rattled inside, so, armed with trusty screwdriver, i busted her open.

the piece that is the culprit is a little tab, that looks alot like those paper clip deals,

remove all the screws from the back, leaving with you this,

take all the screws off the board, taking care to also remove a screw from the back, that is attached to the board, that isn't obvious,

carefully lift the board up, and set it like so,

the arrow indicates where the tab is to be locked onto

take the tab in finger and hand, and press it against the side, so as to open it, so it snaps on. The arrow indicates the angle of how you should put pressure on it.

screw everything back in, and voila!

that is quirky design flaw of the RPs, I've had to do it 3 times, also fixed my buddy's rp150 in the same way.

hope that helped, i made this guide as i know the RP series of pedals are fairly popular, and I doubt im the only one with the problem

goodluck, and happy riffing!