Vintage Synth Repair

Hey all,
I was recently given a “dead” Wavestation EX. Been fixing it up over the last little while, and it’s now working much better. However, a couple of the buttons under the display are not working. “Bank” and “Midi”. The bank button can be worked around, but the Midi button seems to contain some unique menu items. 
I was hoping to simply use an editor, and just do some sysex dumps with something like Midi-OX. However, Midi OX doesn’t seem to communicate fully with the synth. It does send accurate midi note info to the Korg, but the sysex info does not get sent. 
I’ve tried many different combinations in Midi OX (buffers, etc), but with no success.  And the WS memory is NOT protected. 
Does anyone out there have a Wavestation? Maybe we can compare procedures?
Or maybe you have some ideas for fixing the buttons?
Thanks,
Jim Blair
Ape Island Sound
Nanaimo, BC
Canada