quadra thru midi splitter problem

got an mpc500 with the latest OS, an evolver and a blofeld. Those three should be connected via midi out through a quadra thru from midi solutions.
Nothing happens from there on, the indicator LED stays off.
The thru box is fine if i connect it directly to my master keyboard, the mpc's midi out also works if i hook it up directly to one of the synths.

Words of wisdom anyone?

thanks

It seems to me that you have to check this first:
http://www.midisolutions.com/faqs.htm#Power

Have a look at the list of devices not supporting the MIDI powering feature (MPC 500 is in there). They (midisolutions) offer a power adapter to tackle this problem.

thanks for the answer, the mpc500 is in that list because of me, I contacted them after the testing I did. I tried several midi cables, my motu ultralite, mpc via other devices with midi thru and everything else. It's definately the mpc that is not powering up the splitter.
Akai said there were no voltage problems and I should contact midi solutions so I did. The power adapter would definately help but I just bought the box out of pure lazyness anyway and so far I only got one synth without midi thru.