I'm looking for some detailed specs for a Dell Dimension 8400 motherboard (my friend's system). Specifically, the system for no apparent reason could not be powered on.
The power supply checks out pretty decent, voltages are within specs. So I figure either the power switch or motherboard is bad.
Most of the generic instructions available for jumping motherboards refer to a two-pin momentary switch connection labeled PWR, or PWR_BTN. The problem is, on this board, there's a "front-panel connector" with around 30 or so pins, and a ribbon cable going to the front panel lights, power switch, etc. The power switch itself is fairly inaccessible, and I don't see any instructions provided showing how to remove it.
The cable can be easily removed from the motherboard. Where can I find out which of the 30 pins are the correct ones for starting the power-on sequence? Just my luck, the Dell Support Forum website has been down the last few days.
If you cant identify or get to the pwrsw pin, look for the grey wire on the 20+4pin connector, short it to a black wire and that in effect is 'pressing the power switch'
**Edit** As always ofc, be careful playing with electricity and things **
I have encountered this problem - the wire connecting the front switched to your motherboard is not working you have to replaced this. There are the 6pin and the 24 pin rarely the pins do not connect well with the motherboard. I fix this by replacing the switched (I make another switch). I disassemble everything and use another supply and it work. careful thought.
With the 24-pin connector disconnected from the MB, and with the PS_ON signal (green) grounded, the PSU's fan turned on, the 24-pin voltages were good, and there was good voltage on the drive power connectors. That had led me to think either the power switch or motherboard had the problem.
But when connected back to the MB, there was no fan, and no voltage registering on the drive power connectors, even with PS_ON grounded.
That didn't seem right to me, so I finally got a hold of a known-good PSU, hooked it up to the system, and everything worked fine, power button and all.