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XPS 8700, won’t turn on
I have a Dell Xps 8700 with 12GBs of ram and a i7-4790k. The gpu is a gtx 470 I added later. The psu is 500 watts. When plugged in, the amber light on the motherboard illuminates (indicating that the 5v rail is working), but whenever I press the power button, nothing happens. The power button never illuminates any color. However, when I press the diagnostic button on the back of the psu, the fans (pc case, gpu, and cpu fans) spin up to full speed, but nothing else happens. When I stop pressing the button, the fans turn off. Someone please help me, I was planning to use this pc as a NAS and a backup pc if my main one breaks.
redxps630
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July 1st, 2023 19:00
Re: the green led light at the back of the PSU only turns on when I’m pressing the diagnostic button.
If the green led is steady and psu fan turns on when you press the bist button, it would suggest psu passes bist test.
How to run self-test using the button on the PSU
if possible find another working 24/4 pin psu to double check. otherwise by dx of exclusion it is probably a motherboard issue. cpu almost never dies from normal use.
TheTechTinkerer_
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July 1st, 2023 10:00
I forgot to mention I tried shorting out the power button pins, but to no avail.
redxps630
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July 1st, 2023 10:00
Try replace cmos battery with a new battery and clear cmos settings via motherboard RTCRST jumper.
re: when I press the diagnostic button on the back of the psu, the fans (pc case, gpu, and cpu fans) spin up to full speed
this suggests psu is delivering power to system.
TheTechTinkerer_
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July 1st, 2023 12:00
Thank you for replying.
I tried what you suggested, but, unfortunately, it did not work. Do you have any other ideas?
TheTechTinkerer_
6 Posts
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July 1st, 2023 15:00
The 500w one is the stock psu; it has the correct connectors for the gpu, which I added later. I’ve tried other PSUs with and without the gpu, but unfortunately, it did not work. By the way, I messed up; I have the non-k version of the i7-4790. I forgot to mention that the green led light at the back of the PSU only turns on when I’m pressing the diagnostic button.
redxps630
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July 1st, 2023 15:00
If you still have the stock oem psu that was known working, use it to test the motherboard. I would remove the video card from motherboard. connect a VGA cable to motherboard integrated VGA port.
Re: when I press the diagnostic button on the back of the psu, the fans (pc case, gpu, and cpu fans) spin up to full speed, but nothing else happens
you want to test whether the stock psu can produce a Dell logo video signal. another test you can do is remove all ram from motherboard, press psu button to test whether motherboard beeps. no beep is bad sign.
TheTechTinkerer_
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July 1st, 2023 16:00
I tried removing all the ram and pressing the psu button, but got no beeps. Could this mean the motherboard is failing to deliver the 12v and 3.3v rails? I know the psu is fine. The 5v rail is presumably fine because the 5v fans spin up to full speed when holding the diagnostic button (not the power button.) does this mean I need to replace either my motherboard or cpu?
TheTechTinkerer_
6 Posts
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July 1st, 2023 19:00
Great, thank you! I will buy a used working mobo, and let you know how it goes!