Exchange tips and tricks for the Akai MPC4000
By Clint Mon Oct 01, 2012 2:12 pm
Other things to consider to cure locked/ crashing FX are:

1. Initialising the unit.

2. Removing and reseating all connectors/ PCB's.

3. Re-installing the OS might help.

4. Try to select the FX from all available screens.

5. Reboot, Reboot, Reboot...

6. Use external FX, or break down in tears.

If all else fails the EB4JS FX board is shared by the Z4 and Z8 rack samplers.
By Clint Wed Feb 06, 2013 10:59 pm
For the record, fired up the MPC4000 yesterday to look for some files on the HD. The FX issue I was having has returned. I got the FX working properly once out of twenty attempts, all other times selecting FX from the FX screen either freezes the machine or returns a fatal error code. The rest of the machine functions as normal so long as I do not attempt to use FX. Faulty FX board is most likely the culprit, I'll look out for a replacement...
By MPCdawk Thu Feb 07, 2013 12:38 am
clint246clint wrote:For the record, fired up the MPC4000 yesterday to look for some files on the HD. The FX issue I was having has returned. I got the FX working properly once out of twenty attempts, all other times selecting FX from the FX screen either freezes the machine or returns a fatal error code. The rest of the machine functions as normal so long as I do not attempt to use FX. Faulty FX board is most likely the culprit, I'll look out for a replacement...


Bummer!

http://www.ebay.com/itm/400397658711

I wonder if it's a power supply issue - not with the main power supply, but I did notice that there's a couple of electrolytic capacitors on the FX board, presumably to remove voltage fluctuations to the FX chips as the whole board seems to piggyback on the power lines of another board.

Once these electrolytics start to dry out inside they start not holding enough charge for whatever they're supposed to be supplying. The result is a logic IC not starting up properly, that is the program that it's running gets corrupted.

Just a theory, but stable voltage is critical for logic circuits, and this FX board does not have its own power lines, so I believe it's pinching the power from the other board which probably doesn't have much spare, hence the filtering caps on the FX board (or kludge/fudge/jury rig as some might call it).