Help! MPC1K is randomly switching pad bank, stopping seq!

Hi-

Extremely frustrating problem here!

Everything appears to be working ok at first. Load samples, kits, whatever, etc. Knock in a basic sequence, loop, press play.

Then, as I add more parts, the MPC will randomly switch me to pad bank C, (but sometimes B) and then stop my sequence!

It only does this when I push buttons or hit pads on the right side of the case, and only when I do so with a little bit of pressure behind them.

In fact, I've tried knocking on the right side of the case and the same effect is achieved--switch to C, stop sequence.

I'm sure that something mechanical is messed up in there--it's not a software problem. I recently took the MPC on an airplane, and I'm worried that something is damaged inside--maybe one of the ribbon cables or chips is loose?

Has anyone had a similar experience, or do any technical gurus happen to know what kind of looseness or mechanical error would cause such a thing to happen?

Thanks,

Tim

Definitely something up with the right PCB, or the buttons on it.

It can't hurt to open it up and check all the cables (unplug and reseat them, too, it could be a bad connection even if it doesn't look like it).

Otherwise you might want to check for any cracks or anything on the board, maybe have a look for anything unusual on the underside, where all the circuit traces are.


But I would guess it's one of the tact switches that's shot, unfortunately it might be hard to tell which one.
The buttons are wired in a grid pattern (to allow for the processor to read all of them with fewer connections), which makes it so that if one is malfunctioning (sounds like in your case, it's connecting the circuit even when it's not pressed), any number of side effects can be triggered.
Check out the switches underneath the plastic button caps, see if any are obviously busted.
With the matrix wiring, it's hard to tell which exactly is messing up.

thanks.

tact switches being the cursor buttons, "mode", "window", "main", etc, right?

I'll take a look under there. It seems like something is jumpering some connections or something whenever I knock on the case or hit a pad above 110-ish velocity--almost like a loose screw rattling around in there or something.

yep - the tact switches are the actual electronic buttons soldered onto the pcb, under every button on the mpc.

they look like this:


or this, for the bigger rec/play/note repeat buttons:

(just the first images I found, but they happen to be about to scale, relatively)


The stock MPC1000 comes with cheapo small tact switches, so those can die easily.
If you end up replacing them, use much higher quality ones, like ALPS-SKHHAKA010 switches, or equivalent, OMRON B3f-1020.
There are forum topics somewheres on here that have more info, just do a search, if you think you need to replace any switches.

Hi, did you fixed it?