I thought I mentioned last week that I have the PCW8256 service manual. Amstrad service manuals are just shcemaitcs and parts lists -- almost no faultfinding infromation. Actually, I prefer that sort of manual :-) Anyway, the only problem could be that I have the manual for the 230V mains version (not suprisingly), and it appears that there is no way to make that PSUmonitor board work on 115V mains (the mains input stage is just a bridge rectifier feeding a single smoothing capacitor, it couldn't be trivially changed into a voltage doubler). However, assuming that the secondary side ofthe supply is the same in all versions, here goes. The fact that your 24V line is present and correct inplies that the mains side of the PSU is working correctly. This is a somewhat odd PSU (for a computer) in that it rectifies the mains, chops it, and feeds it to a SMPSU-like transformer, but doesn't apply any regulation feedback from the outputs to the chopper stage. Instead there are linear regulator circuits for each of the outpuyts. I'll describe the 12V one, because (a) it's simpler than the 5V one (no overcurrent protection circuit) and (b) the 5V regulator depends on the 12V one, so if the 12V is missing or incorrect, the 5V won't come up either. The regualtor circuit uses IC5003, an AN6531 device. It's powered from the 'raw' 24V supply, it feeds Q5003 (2SD1666) which is the pass transistor for the 12V supply. There's feedback from the 12V output (emitter of that trasnsitro) to the regulator chip via a potenital divider consiting of VR5002 and R5021. Start by measuring the collector voltage of Q5003. According to the schematic, it should be 13.5V, but that is unregulated, of course. If it's missing (and I think it will be), check D6010 (the half-wave rectifier for this supply line) and ICP502 (an 'IC protector' fuse in series with the diode). This is lavelled ICP-N75 on the schematic, I forget how to work out the current rating from that (is it 75+40 = 3000mA or 3A???) My guess, actually is that ICP502 has blown. It looks like a 2-lead TO92 pacakge alonside the chopper transformer, and is the only overcurrent protection for the 12V supply. The question is 'why'. Maybe the disk drive motor took too much current or something. You might want to look into that. -tony