OFFLIST (due to being placed on moderated mode) was Re: Problems with

I really dislike that abreviation. 'System Planar' I can tolerate, but not that one... [...] Alternatively, you could try something that's gone out of fashion now, but which IMHO is the _only_ way to repair a computer (or for that matter anything else). And that is to make measurments, deduce what's working and what's not, and fix the faulty part. It's already been suggested you get a multimeter (and I'll go along with that). A logic probe (if you can still find one) is useful too. More complex and expensive test gear includes an oscilloscope and a logic analyser. You probably don;t need those at this point. Try to get the IBM Personal Computer Techncial Reference Manual. It contains full scheamtics of the motherboard (and in early editions the I/O boards, these were later moved to the Options and Adapters TechRefs). This is how I'd attack this problem. Assuming you are prepared to risk the motherboard on this PSU (and to be honest it's not much of a risk), conenct the PSU to the motherboard and power up. Using a voltmeter (voltage rages of a multimeter), check the power voltages at the PSU connector on the motherboard. If any are missing/wrong then either the PSU is faulty (and needs repair), or there's a short somwhere on the motherboard (maybe a decoupling capacitor). If the votlages are OK there, check them at the power pins of a few ICs. If they're msisign there, there's an open-circuit on the motherboard. Now, using the logic probe, check that the CPU clock is present and that the thing is not being held in the reset state. Check that the address and data buses arte active (toggling signals). -tony