Eblo

M-Audio Keystation Pro 88 MIDI Repair

I recently had to take apart my new-to-me M-Audio Keystation Pro 88 keyboard controller. The MIDI Out port had flaked out. I bought it as a floor display and I think the MIDI cords got yanked out of the back more than once which resulted in broken solder joints. I've used it for a while as is, but the plug always felt loose and I wasn't surprised when it went totally Tango Uniform on me. So I busted out my screw driver, multimeter, and soldering iron to effect a repair of the MIDI jack.

When it came to dismantling the board, it looked fairly straightforward to me, but I searched online to see if there was any guidance to be had. I didn't find any, so I decided to take some photos along the way and post this little write-up in case any one wanted to follow in my footsteps. WARNING: I am not an electronics expert by any stretch. I'm just a guy who likes to take broken things apart and fix them if he can. I get lucky and occasionally things work the same or better after I put them back together, but follow this guidance at your own risk. If you have any doubts, take your board to some one with experience and/or insurance.

1) To work on the keyboard, I took it off its stand and placed it on the floor. I tipped it to that the back of the board (with the ports and power switch) was facing upwards. On my carpeting, it would rest like this on its own, apparently with no pressure on the keys, but I didn't trust it to stand on its own and kept a hand on it while it was propped up thusly.

2) The back of the board is made up of one continuous plate of metal. To remove it, I removed all of the screws on both the back and bottom of the board that attach the metal plate to the frame. Note that on my board, the screws on back had little clear plastic washers presumably to protect the finish of the board. I kept an eye on those so I wouldn't lose them. Also note, NO OTHER SCREWS NEEDED TO BE REMOVED! Just the ones holding the metal plate down from the outside.

3) Once all of the screws were removed, I took a while to figure out how the plate came off because it was still held in fairly tightly. I was trying to open the back panel up by lifting up from the bottom of it, but this didn't get me any where. The trick was to use a broad putty knife and pry up at the back plate from one end of the board. The plate has 90 degree bends at both the top and bottom that fit tightly into the frame of the board, so it has to be lifted straight out of those tracks.

4) I found that once the panel was loose, tipping it 'bottom forward' while looking at the bottom of the board was the best way to get at the ribbon cable connectors. There wasn't a lot of room on these ribbon cables, so I was careful not to over stress them and kept the back plate as close to the board as I could. I believe all of the connectors are unique, but it's always a good idea to label or at least photograph them before removal.

5) Once I removed all of the connecting wires, I removed the 8 screws holding the the circuit board to the back plate.

6) After using my multimeter to confirm that the jack itself was still good - the solder joints were just broken, I resoldered the jack to the board, tested the connections with a MIDI cable and my multimeter and put everything back together.

Note: The one tricky bit I found when reassembling everything was that the power and USB jacks did not want to fit nicely through their cutouts on the back plate. I cranked down the screws before I realized this and risked screwing up those jacks while repairing the MIDI. I removed the board one more time, made sure everything was seated properly, and THEN screwed the back plate back down.

That's it! As easy as 1-2-6, I fixed my MIDI controller. If not for my recent Brain Machine project and my first experience soldering on a Printed Circuit Board, I don't know if I'd have had the guts to attempt this repair, but it was really not a big deal when all was said and done. The toughest part is that the board weighs nearly 50#. I could have hurt my back getting it off and back on the stand :)

I hope this helps some one out there who needs to crack the case on his/her board. If you have any questions, let me know: oblivion at ratula dot net.