So after I replaced all 35 burnt out LED drivers, and the micro, I took it all back to the factory yesterday, but ran out of time to connect it up myself, so I said I will come back this morning.
I told the same guy ( who got the red and black wires revered )not to plug anything in till I have checked it.
They would lay all 36 displays out on tables in the factory, for this morning.
There was me worried about humidity and corrosion in Central Africa, but lo and behold I get in there this morning, and 4 of the displays are soaked in pidgeon crap ! all over the new chips, and the LEDs.
So I bring back the effected boards and washed them off with meths, and will spray them with clear laquer when they are really dry ( and tested )
They have always had a pidgeon problem in the factory, but didnt think about it.
They have now hung sheets of bubblewrap above the displays while testing - hindsight !
This has turned into the job from hell, but at least I did spot a little bug in the software that I am busy with now. The next order is going to be massive, so I have to bite the bullet for now .... 