Mmt8 - fixable. Works great until....?

Alesis MMT8 . Grey model. 1.11 OS. Bought off [eBay] about a year ago. When I tested it on receipt I’m pretty sure I recorded (and played back) a basic sequence from a motif so looked to be fine. No Paypal dramas…

So a year later - I pull out the unit. Original power supply, not even much dust on it and fire it up. It works fine. There was an old sequence and playing play had it go through to another synth fine.

All good - all great. Just…it won’t record in any MIDI data anymore.
Its crazy, all lights and buttons work fine. I’ve opened up, and no sign of physical wear or dust.

For the MMT8 owners/ex owners, its nothing more complex than selecting a SONG/PART, hitting record, choosing your track, hitting play and waiting for the countdown is it ? (I checked the manual). It says its recording - but I can’t see any event data.

It can’t be the cables, they work fine on other synths. Have used various controllers and even a mac with ableton to send midi data over to thr mmt8.

Can’t even find anywhere in the UK where I can get this fixed. Checked memory (100% available), LCD is fine. Click track ok,and no errors or indication something is wrong. Has anyone else heard of the MIDI IN interface simply giving up. Again - no sign of damage/dust etc.
Seeing this forum gives me some hope someone might have an idea of what chips need replacing.
Any help welcome.
Mark