Hi there Hugo (YusAlcala), I hope you are well and this finds you having a really nice weekend. I have measured the voltages on two systems, a PC5286 and PC5386. Both are extremely similar. Files are here: http://ns4.reboot.net.au/hardware/amstrad-PC/ PC5286 I have two versions of the motherboard with silkscreen V4 and V9. There is a difference in the connected negative lines for 12/5volt. PC5286v4 and PC5386 is same, no differences. My experiments were thus: C1 1-2 12v 1+ 2- C1 4-5 5v 5+ 4- C1 6-4 5v 6+ 4- C2 3-4 12v 4+ 3- C2 1-2 2v 1+ 2- C2 2-3 6.5v 2+ 3- (Crossed - 5/7v rail) C2 1-3 12v 1+ 3- C2 2-4 5v 4+ 2- Best Wishes, Al Boyanich (VK2FVAX / Uridium on IRC)