Author Topic: Dead Desktop  (Read 1581 times)

valkyrie

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Dead Desktop
« on: 21 October, 2017, 07:30:56 pm »
This afternoon I powered up my home desktop PC for the first time in a few weeks. Booted up normally and I started iTunes, Mail and the web browsers before going off to do something else for a while. When I came back to the PC the screen was showing iTunes but the computer was completely unresponsive. Mouse, Ctl-Alt-Del both had no effect. So I turned it off and on again. It seems to get a part way through the start sequence then fail before going back to the start. Flashing light on the monitor that indicated it's not got an input signal just keeps flashing, screen stays completely black so I don't see the Bios splash screen or anything else. Clearly the PC is buggered. Question is where do I start with the fault finding? Graphics card/HDD/Ram/motherboard? All suggestions gratefully received.
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BrianI

  • Is it a bird? Is it a plane? No, it's Lepidopterist Man!
Re: Dead Desktop
« Reply #1 on: 21 October, 2017, 07:36:49 pm »
This afternoon I powered up my home desktop PC for the first time in a few weeks. Booted up normally and I started iTunes, Mail and the web browsers before going off to do something else for a while. When I came back to the PC the screen was showing iTunes but the computer was completely unresponsive. Mouse, Ctl-Alt-Del both had no effect. So I turned it off and on again. It seems to get a part way through the start sequence then fail before going back to the start. Flashing light on the monitor that indicated it's not got an input signal just keeps flashing, screen stays completely black so I don't see the Bios splash screen or anything else. Clearly the PC is buggered. Question is where do I start with the fault finding? Graphics card/HDD/Ram/motherboard? All suggestions gratefully received.

Make and Model of desktop? Is it an Apple device? Or a PC? Manufacturer, or a "computer shop" home build?

Do you hear any fans at all running in the desktop, or can you see any lights through any vents on the rear?  It could well be the power supply which has gone on to pastures new.  If you have a generic PC, then it's pretty straight forward to source a replacement power supply unit. If it's something like a Dell, or other Branded Manufacturer, they may have used specialist modified PSUs in their machines, which may not be as easy to replace.

Afasoas

Re: Dead Desktop
« Reply #2 on: 21 October, 2017, 08:31:20 pm »
I wouldn't jump to the conclusion it's dead yet.

Try hard powering everything off - including the monitor. Switch off at the plug and allow sufficient time for all the caps to discharge.

If that doesn't do it, double check all the monitor connections  are snug, ensuring the monitor is switched on a good 5 seconds before booting the PC and has the correct input mode selected (assuming multiple inputs)

If the PC has multiple video outputs (e.g. DVI + HDMI) and the monitor has multiple inputs, try say switching from DVI to HDMI or vice versa.

After that, I'd try the monitor with another PC/input device and just verify that's not fried.

Does the PC have a discrete graphics card or is it all on board?

valkyrie

  • Look at the state of your face!
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Re: Dead Desktop
« Reply #3 on: 22 October, 2017, 12:05:05 pm »
It's a Windows 10 PC, a few years old but high spec when I bought it, Core i7 processor, 6GB of Ram and a Radeon R7 370 2GB graphics card sitting in a PCI Express slot.

This morning I opened the case, gave it a bit of a hoovering and checked for loose connections. Nothing obviously so I switched it on and it booted up. The only thing I could see that concerned me was that the two fans on the graphics card weren't running, even though the heat pipe below them was getting pretty warm, maybe 50 - 60 degrees. Tried re-starting Windows to get to the Bios settings and its dead again. Back to what was happening last night, which is that it starts up, all the fans, disk etc whirring away then after about thirty seconds there's a gentle "click" and all stops. Pause for a couple of seconds then the thirty second sequence starts again. This problem started after the PC had been on for over an hour, so now I'm thinking that it might be the power supply overheating.
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Re: Dead Desktop
« Reply #4 on: 22 October, 2017, 12:07:16 pm »
Sounds like the PSU.
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valkyrie

  • Look at the state of your face!
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Re: Dead Desktop
« Reply #5 on: 22 October, 2017, 12:11:14 pm »
Extra info - there are some small surface mount LEDs on the main board. Green is on while it's starting up, then Amber for the couple of seconds it's completely dead then Green comes back on when it restarts.
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Re: Dead Desktop
« Reply #6 on: 22 October, 2017, 12:20:56 pm »
Are you able to beg steal or borrow another PSU to try? What happens if you remove the GPU?
Get a bicycle. You will never regret it, if you live- Mark Twain

Afasoas

Re: Dead Desktop
« Reply #7 on: 22 October, 2017, 05:02:46 pm »
If the fans aren't spinning on the GPU, try pulling it out and rely instead on the i7s GPU.
Hopefully your BIOS will make the switch automagically.

valkyrie

  • Look at the state of your face!
    • West Lothian Clarion
Re: Dead Desktop
« Reply #8 on: 22 October, 2017, 06:56:52 pm »
This afternoon I went to my local PCWorld and bought a new Power Supply for £60. That got the PC up and running again. After a few hours of running normally I shut it down to put the covers back on and put it back under the desk. Powering up after that got me a load of odd messages and Windows starting but then stopping at a blue screen of death. Took the cover off, gave everything a shove to make sure it's in place and now I'm up and running. My trust in this PC is at an all time low, I think I'd better start making contingency plans.
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Re: Dead Desktop
« Reply #9 on: 22 October, 2017, 07:12:29 pm »
Personally,

I'd find out what the lights mean by looking at the motherboard manual.
I would strip down to the motherboard and reseat everything, maybe replacing the thermal paste.  I would have a look at the hard drive SMART status and look at memory tests. 

Is it worthwhile to dig the video card manual out and see when the fans should be on.

Had something similar when a hard drive was failing.