I bought a Dell XPS-8900 tower PC. The PS does not have an on/off switch on it. When I plug in the power cord, the PC powers on for about 5 seconds and then goes off. Then pressing the power button on the top of the PC, it powers on and boots into Win10.
TESTING WITH 2 OTHER POWER SUPPLIES:
GOOD - I tried an old Antec SL400 (400 watt) PS that is so old that it has a 20 pin mobo connector and only 4 pin molex peripheral connectors (plus the 4 pin P2 connector). Installed molex to SATA adapters and It works exactly exactly like the stock PS. So all is good with this old PS.
BAD - I tried an Antec Earthwatts 500 watt PS that has the 24 pin mobo connector, 4 pin P2 connectors and SATA power connectors. When I plug in the a/c power cord and switch the PS on, the PC powers on for about 5 seconds and then powers off. But no matter how I press the power on button on the top of the PC, the PC will not power on. IOW, nothing happens.
HERE'S THE KICKER: I connected the stock PS and went into BIOS. The a/c recovery was set to OFF so I set it to ON. I connected the Earthwatts PS and when I turn the power switch on the back of the PS on, the PC powers on and boots into Win10 fine. I put a small fan blowing into the PC's case and used the PC all day and the PS worked fine and normal. IOW, the Antec Earthwatts PS works fine. It's just not compatible with the Dell XPS-8900 PC if the BIOS a/c recovery is set to OFF.
INVESTIGATION OF PS VOLTAGES & SIGNALS: I set the BIOS to a/c recovery OFF and did a back probe test of the 24 pin mobo connector using the stock PS and the Earthwatts PS. After the momentary 5 second power on and off, every voltage and signal are in the same states as the stock PS. ---- When I press the power on button on the top of the PC, the "power on" wire on the 24 pin connector stays high and never goes low. So the Earthwatts PS of course will not turn on. ---- Apparently, during the momentary 5 second power on/off when a/c power is first applied, the PC's motherboard doesn't like something so refuses to pass the PC's power on button to the "power on" signal on the 24 pin connector.
QUESTIONS:
1. Any ideas why the Earthwatts PS won't work if BIOS a/c recovery is set to OFF but will work fine if a/c recovery is set to ON?
2. If I ground the "power on" signal on the 24 pin connector to force the Earthwatts PS to go on (without cutting the wire), will that blow anything in the motherboard? I don't think it will but wanted to get informed answers from the gurus in this forum first.
Thanks,
Skyzoomer
TESTING WITH 2 OTHER POWER SUPPLIES:
GOOD - I tried an old Antec SL400 (400 watt) PS that is so old that it has a 20 pin mobo connector and only 4 pin molex peripheral connectors (plus the 4 pin P2 connector). Installed molex to SATA adapters and It works exactly exactly like the stock PS. So all is good with this old PS.
BAD - I tried an Antec Earthwatts 500 watt PS that has the 24 pin mobo connector, 4 pin P2 connectors and SATA power connectors. When I plug in the a/c power cord and switch the PS on, the PC powers on for about 5 seconds and then powers off. But no matter how I press the power on button on the top of the PC, the PC will not power on. IOW, nothing happens.
HERE'S THE KICKER: I connected the stock PS and went into BIOS. The a/c recovery was set to OFF so I set it to ON. I connected the Earthwatts PS and when I turn the power switch on the back of the PS on, the PC powers on and boots into Win10 fine. I put a small fan blowing into the PC's case and used the PC all day and the PS worked fine and normal. IOW, the Antec Earthwatts PS works fine. It's just not compatible with the Dell XPS-8900 PC if the BIOS a/c recovery is set to OFF.
INVESTIGATION OF PS VOLTAGES & SIGNALS: I set the BIOS to a/c recovery OFF and did a back probe test of the 24 pin mobo connector using the stock PS and the Earthwatts PS. After the momentary 5 second power on and off, every voltage and signal are in the same states as the stock PS. ---- When I press the power on button on the top of the PC, the "power on" wire on the 24 pin connector stays high and never goes low. So the Earthwatts PS of course will not turn on. ---- Apparently, during the momentary 5 second power on/off when a/c power is first applied, the PC's motherboard doesn't like something so refuses to pass the PC's power on button to the "power on" signal on the 24 pin connector.
QUESTIONS:
1. Any ideas why the Earthwatts PS won't work if BIOS a/c recovery is set to OFF but will work fine if a/c recovery is set to ON?
2. If I ground the "power on" signal on the 24 pin connector to force the Earthwatts PS to go on (without cutting the wire), will that blow anything in the motherboard? I don't think it will but wanted to get informed answers from the gurus in this forum first.
Thanks,
Skyzoomer
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