Well at last I have removed and re-installed all parts, switched it on - NOTHING not even the original fault.
Depression sets in.
But one good thing, the test lead set allows me to light it up, on the bench. And upon closer inspection the display is alive.
Re inspect, now a new fault, created when the 12pin plug is resoldered, the upper PCB tracks have not taken, gave it a good dose of heat & solder
but to be on the safe side used some jumper wire to hard wire the pin to the copper track. This is a problem with double sided PCB's.
Screwed it all back together, then one last bench test, bloody hell, not working again, what now.
Crack in C9 pin on the 32pin connector, this is the I/O connector which is butchered and turned 90° upon conversion.
First place to look for faults, as the soldering is a nightmare. Now all working.
Had enough, roast garlic/rosemary lamb is smelling good - I'll put it back in the car tomorrow.