Midi Problems with MPC500

I took a chance and bought a second hand unit yesterday.
Seems to be well cared for, however....

Midi out signals are just bizarre. Even with Soft Thru on, just weird stuff comes out of the midi out. Pitch bends and mostly repeated note off messages.

Midi in messages work very intermittently. I'm playing microkorg XL into the unit. midi channel out matches midi receive channel and track midi channel. Everything is set up properly midi wise.

If I press the C1 key (mapped to A1 pad on MPC) multiple times, it might trigger the sample once.

Using midi cables that work fine with all the rest of my equipment.
Really bummed out about the situation. Definitely a problem with the midi in and out.

I reset the unit to factory settings and upgraded to the 1.31 patch again but still the same problem.

The unit is unusable in its current state for what I want it to do. I was thinking I might try and replace the midi in and midi out sockets but it feels like it's something wrong with the hardware itself.

Before I start taking it apart, just wondering if anyone else has encountered these problems and could suggest anything?

Thanks.

that sounds weird.......do more tests and make sure you aren't doing anything silly. try looking at the data that your mpc is sending with midi-ox or similar software.

make sure you aren't creating a feedback loop in your midi system, this is normaly what causes double notes. (i.e. try connecting just the midi in, or just the midi out)

check your cables again.

if you have really ruled out user error, apart from the midi sockets, the only thing you could replace would be the optoisolator, but i'd want to be sure before doing that. its probably a tiny little surface mount chip. soldering surface mount chips isn't impossible but don't try to learn how to do it on an mpc!

theres a copy of the service manual arround someplace on the net, pick that up asap.

Cheers. I've already done all you suggest above. No dice unfortunately

is it better or worse if you wiggle the midi cables? that would indicate that the sockets are dodgy? (dodgy sockets could result from just one instance of being dropped) they might just need to be re-soldered, at worst you have to replace the sockets and rebuild some pcb traces.

the optoisolator can be damaged by connecting the midi cables to something that isn't midi(70's hifi, smoke machine, etc). the opto isolator is only on the midi input though, the output is connected pretty much directly to the processor.

if the mpc has indeed been fried by some idiot trying to connect it to a 70's hifi you will still be able to get the input working again by replacing the opto isolator.

lots of crazy things can happen if you have power supply problems, if you are using a psu, try batteries.

if you can post a log from midi ox that might help me see what's going on.

i'm not convinced it has been fried though the opto isolator should be either good or **** up, the fact that it's kinda working make me think it must be cables and connectors.

i'd double, then tripple check the cables you are using, try a difernt power source,then open her up and and check the midi connectors.

I will do. Thank you. Much appreciated!

Hi again,

I set up a test, wiggled the cables and checked them with other equipment. All functioning fine. I also used batteries in the MPC500 for this test so problems with the PSU can be ruled out.

The Setup.

I'm using an Oxygen 8v2 (Previously I used a microKORG XL with the same results) to check the equipment.

Oxygen-----> Midi-Ox midi monitor.
Playing notes C2-c#3 gives the following result:


Testing Pitch Bend:


Testing Modulation (CC):



Step 1: Plugging midi in cable into midi out of MPC500
Step 2: Powering on MPC500
Step 3: Loading program and assigning program to track 1 - Assigning samples to pads
Sample sounds trigger when I play the pads, no problem.

Step 4:
Jog wheel to Track Parameters> Midi Channel (Oxygen 8v2 was sending on channel 4, so I'll select that channel for MPC500)

MPC500 repeatedly sends CC information. See image:
Stops after a while.




Step 5:
I'll repeatedly play a simple | kick kick snare kick | Kick Kick Snare snare | using the bottom 3 pads on the MPC500 which have been assigned to (left to right) C#1,C1 and F#1.

The results vary:
Example 1: Starts out ok - Kick Kick Snare Kick | Kick.... Transmits but then sends a repeated C-1 note off signal while I continue to play the pattern.



Example 2: While playing the same pattern above the MPC500 then sends repeated Bank MSB CC messages. *Note, these repeated messages happen many times per second, not in response to myself hitting the trigger pads.



Example 3: While playing the same pattern as above, the MPC500 starts sending repeated pitch bend messages and then repeated Bank MSB messages


Step 6:
I will now plug the Oxygen8v2 midi out into the midi in of the MPC500 so that I am using the Oxygen keyboard as a controller of the MPC500.
Before plugging in the oxygen keyboard I go to the Midi Sync options and select "Receive Channel": ALL and "Soft Thru" as ON.
When I jog wheel to Soft Thru, the MPC500 sends a few SysEx messages.





Step 7:
I'll now continually play C1 (snare) and C#1 (Kick) on the Oxygen keyboard:
Example 1 - The MPC500 sends one note on message and then a repeated pitchbend message


Example 2 - Trying again - The MPC500 sends repeated repeated PC messages.


Example 3 - Trying again - The MPC500 sends repeated C-1 note off messages as well as repeated C#1 Note on messages



Finally playing the MPC500 pads again, the MPC500 sends repeated Key aftertouch messages. Note that the incoming midi channel is channel 10



Any more suggestions are greatly appreciated as I'm completely lost!

How about removing the ram card?

hmm, it seems like you really do have problems.

there is definatly something wrong with your mpc

good call on checkking the ram card, ralphyaris.

try with no cf card too. its a long shot but totaly possible that a defective memory card could cause any number of weird symptoms.

if it's not either of those then you have a trip to a repair shop on the cards

sorry about that.