Quasimidi TechnoX not responsive

[belzrebuth]

Hi all,
I've been given a Quasimidi TechnoX which does not respond to MIDI, outputs no sound and has black squares on the LCD display.
It powers on and all voltages are correct but no other sign of life apart from various clock signals and limited activity on the EPROM pins.
My guess is that the there's something preventing some kind of CPU to start or a communication error of some sorts, there's also a UART in there as well with no notable activity (MC6850).
Only thing I've noticed from probing around is that a 16MHz XTAL does not output a clock signal (or the clock gets drowned somewhere?) note that there's some DC on the quartz pins so I initially thought that it was the quartz but I've replaced that and no change.
This lost clock signal seems to be a big clue because it's on the side of the board where the UART and some GAL ICs are located so I'm guessing other important stuff are there as well.
I thought about injecting a 16MHz in the quartz pins but I'm unsure of the amplitude of said signal or any other details I might be missing.
There are some difficult to recognise ICs in there and a couple of big PLCC ICs which have their top surface scratched.
The whole instrument looks very cryptic.
Is anyone familiar with these machines or have any info (schematics) about them?
This belongs to a friend and I've actually seen it working recently; it just died on its own, no rough life or anything.

[madtheory]

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