Can grounding the green PSU wire while its connected to a motherboard ever damage a motherboard? I've made a few motherboards show signs of life by doing that, and two of them even managed to show the BIOS boot screen (but couldn't make them turn on the usual way).
A friend of mine had a Socket 754 Nforce3 (MCP250) motherboard suddenly shut down on him, and it wouldn't turn on when its power switch jumpers were shorted together. So I hooked it up to a known good PSU (300W Delta with all Rubycons and Nichicons) and grounded its green Power-On through a 200 ohm resistor. That made the CPU fan turn on and stay on, but there were no beeps or video (no built-in video; used AGP and PCI video cards). Also the Nforce3 chip got hot enough to make the circuit board reach 110C on the bottom side (not measured until probably 3 seconds after turn-on). The CPU, video card, and memory work fine in another motherboard. Nothing looks discolored. I've tried pressing on the Nforce3 chip while trying to turn on the motherboard through its power switch pins, but nothing happens.
I don't think it's a matter of bad caps because he recapped it a few years ago with all Nichicons, and his soldering looks good under magnification.
A friend of mine had a Socket 754 Nforce3 (MCP250) motherboard suddenly shut down on him, and it wouldn't turn on when its power switch jumpers were shorted together. So I hooked it up to a known good PSU (300W Delta with all Rubycons and Nichicons) and grounded its green Power-On through a 200 ohm resistor. That made the CPU fan turn on and stay on, but there were no beeps or video (no built-in video; used AGP and PCI video cards). Also the Nforce3 chip got hot enough to make the circuit board reach 110C on the bottom side (not measured until probably 3 seconds after turn-on). The CPU, video card, and memory work fine in another motherboard. Nothing looks discolored. I've tried pressing on the Nforce3 chip while trying to turn on the motherboard through its power switch pins, but nothing happens.
I don't think it's a matter of bad caps because he recapped it a few years ago with all Nichicons, and his soldering looks good under magnification.
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