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XPS 720, won't power up
I think I am facing a losing battle but will ask anyway.
I have an XPS 720 that was working then stopped; symptom being the power does not stay on, i.e. press power button, lights go on and fans start but then everything is off after about a second.
I replaced the power supply, made no difference.
I recently replaced the motherboard, power came on and stayed on but nothing else happened i.e. no beeps from BIOS and no output on graphics card (card is pretty old, I do not have model details to hand). I had tried everything from bare board to board with cpu, ram, graphics card and hd connected; same.
I tried with a known working CPU, as above.
So I then refitted the original power supply, plugging in the mains cord or pressing the on button does nothing.
I am about to fit the other power supply but expect either the same as before or nothing; last option is to try another graphics card but the fact that there are no beeps e.g. no ram installed indicates either the cpu is dead and/or the motherboard is dead too.
Any ideas appreciated but I suspect this is destined for the bin.
RoHe
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January 26th, 2019 17:00
Sure the replacement motherboard works and has a fresh CR2032 battery installed? Reinstall everything on the new board after removing the old battery and pressing/holding power button for ~30 sec. When everything is correctly installed/connected, install the fresh battery.
Is the "known working CPU" identical to the original? Otherwise, are you sure the replacement CPU is compatible with this motherboard? Just because it fits into the socket, doesn't mean it's compatible. BIOS determines CPU compatibility.
Can we assume you applied fresh thermal paste on top of the replacement CPU before attaching the heat sink?
Are all fans working?
Power off, unplug and press/hold power button for ~15 sec. Use flashlight to examine all USB ports for possible damage. A shorted USB port could cause those symptoms.
If you boot up with everything installed except any RAM, but don't get a 2- or 4-beep error code, then the motherboard may have failed.
mp_108
175 Posts
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January 28th, 2019 13:00
thanks for suggestions; I will look into the battery; just measured it and its it dead; I did power up with the dead battery and then again after I removed it - I was certain that if the battery is dead, the computer would boot and complain about dead battery but maybe I am wrong.
yes - fresh thermal paste.
RoHe
10 Elder
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44.3K Posts
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January 28th, 2019 16:00
First thing then is to replace that dead battery...
And keep in mind, since the battery died, BIOS got reset to the default settings. And those defaults may -or not- be the correct settings for your specific hardware setup.
The XPS 720 Service Manual lists BIOS settings options but doesn't indicate which ones are the defaults.
Let's see what happens after you replace the battery and if there are any beeps, error messages, diagnostic LED error codes, and color of power button and if steady or blinking, if it still won't boot.
BTW: Do you have the Dell Drivers and Utilities Media CD? If PC won't boot from hard drive, you could try booting from that disk to run the hardware diagnostics...
mp_108
175 Posts
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February 9th, 2019 07:00
Thanks for suggestions but new battery made no difference. It will be listed on ebay, I can't see how spending any more time on it is going to change anything.
RoHe
10 Elder
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44.3K Posts
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February 9th, 2019 12:00
Sorry that didn't help.
If you're going to sell it, make sure you nuke whatever's on the hard drive with something like DBAN (free), first.