How to begin a repair or service of a Korg M50-88 by gaining access inside.
The following is probably similar to the proprietary information used by service/repair providers licensed by Korg Inc. However, I have not seen a service manual to date. As the gatekeepers, licensed Korg repair people insure quality parts and control. However, such negotiations can be expensive and time consuming. A site for buying Korg service manuals can be found on the Korg Forum.
Please read the entire narrative before initiating a procedure, and, remember, you will be violating any warranty.
The operation for getting inside the Korg M50-88 is remarkably simple and I suggest that owners of the 61 and 73 key versions may consider the following as a template.
First of all, remove all the plugs and jack accessories from the backside, including the AC adapter. You will not need to remove any screws on the backside.
Next, set the unit on a work-type or padded tabletop with backside down. Simply locate and remove the eleven (11) screws around the perimeter of the base/particle board at back and sides; plus the two (2) screws securing the joystick assembly; thirteen in all (all with the same dimensions.)
Now you can carefully, open it like a book (but not all the way) as you slowly drop the particle board base toward the table top as if it were hinged. Then locate the single multi-pin connector running from the keybed to the receptacle socket on the central CPU board and carefully disconnect it. You’re done!
It won’t be necessary to remove the screws holding the keybed down, nor the keybed guard rail, unless you are addressing a problem there. However, it wouldn’t hurt to remove the remaining screws (noting 3 different sizes), shake the keybed along with the individual keys, and, thus, remove the dust, debris, and soot that has accumulated therein. I noticed a few white plastic chippings but have yet to locate their source.
The reverse process, of course, begins with the pivot where attention is directed toward the connector and its socket on the CPU board.
You will notice how compact the circuitry is. And you will rue the day, if you fiddle with it without the proper skill and tools, you could find that you have trashed the unit (an expensive and heartbreaking education).
If you love this Korg, as I do, proceed with the greatest caution as you attempt to address any problem, and patiently pursue the info that you want, including the various tech-support sites online and by phone. Good luck on your new adventure.