Computer died in the night and wont be revived
June 10, 2018 12:52 AM   Subscribe

Follow up from this question. My computer has now turned off for good, it seems.

For a couple of weeks my computer stabilised and stopped rebooting or shutting off, I thought it had just been a loose cable as it rebooted more when I was in the room with it. Thursday or Friday it had 1 or 2 reboots then on Friday, I came back from lunch to find my screen black with just a blue windows logo and some dots underneath. I don't know if that was another forced update because I wasn't at my desk to tell it to snooze. After the update my mouse and keyboard stopped working and Windows kept saying "USB device not recognised - every 2 minutes until I had to turn off notifications). I'm using RDP so the mouse and keyboard not working wasn't a major issue. Then at 3am on Saturday it went into a reboot loop - don't think it was getting much further than post. I had to turn it off at the PSU because it was waking me up.
Saturday morning, I put the switch back on and pressed the power button but nothing happened. I bought a new PSU and installed it this morning, it whirred on when I turned it on at the socket but then shut down. I pressed the power button but it did nothing. I turned it off at the PSU switch again and after a few seconds turned it back on and it whirred up again and then shut down. No output to the monitor.
I plugged everything back in (one time I was building a computer and it wasn't booting properly because there was no keyboard plugged in) and it seemed to come on longer, long enough that I got a beep - 1 long, not very well sounding beep (but not the kind of screech that you get when the CPU fan isn't connected, I don't think anyway) and it shuts down. I google the Gigabyte post codes (couldn't get MOBO specific ones because I couldn't find the model number written on it an is 10 years old, I've moved twice since I had it, no idea where the manuals are). 1 long beep seemed to mean the memory wasn't installed correctly, I took the RAM out and it didn't do the long beep, it whirred up then shut down - 1 of the times it whirred up and gave me a normal post beep before shutting down, still no output to the monitor. I swapped the RAM out for some different RAM and it did the long beep and shut down again.

Some of the time when I turn it on at the PSU it didn't come on at all but I couldn't find any consistency in that.

I know its old and I should probably just get a new one but I really don't want the hassle right now. I work from home so its my work computer so I need to fix it, if it can be fixed. I'm worried the MOBO is dead though (and at that point I might as well get a new one)
posted by missmagenta to Computers & Internet (6 answers total)
There are several possibilities for your computer to act as it does, and I don't think it's worthwhile to keep replacing bits until you've found the culprit.

As you know how to build a computer system: get a new one, and install the disk from this one into it. Then you have the choice of setting it as the C: drive and the new disk as D:, or the other way around.

* Old C:, new D: - you'll have the system as it was, settings, data, the lot, on new hardware. You may need to install a few drivers for new bits of hardware that the installation doesn't yet know how to handle. Downside is that you're running on a disk that's 10 years old, with a fair chance that it will fail in the not too distant future.

* New C:, old D: - fresh installation, you need to set your preferences, add all the programs and utilities that you have collected over the years. Data is on D:, should be copied over because of possible failure.

* Old C:, new D:, fancy option - add those drivers as above, then (using a disk cloning tool) write the entire C: drive on to D:, wiping what was there. Remove the old drive and turn D: into C: (or keep the old drive in and swap them around).
posted by Stoneshop at 2:02 AM on June 10, 2018

Response by poster: I have 3 disks, because I did that the last 2 times I got a new computer!
posted by missmagenta at 2:43 AM on June 10, 2018

In the previous go-round, I'd missed the fact that this is an older computer. Given that it is, the most likely cause I can think of for the behaviour you're describing is bad caps in the motherboard's on-board DC-DC converters.

Bad caps suck. The only good thing about them is that in most cases you can spot them with a simple visual inspection.

If that's what it is and you're handy with a soldering iron, you can replace them though the process is a pain in the arse; the lead-free solder used to assemble motherboards melts at a relatively high temperature and doesn't much like cooperating with hand desoldering tools.

Least painful method I've found involves melting a large blob of solder across both the capacitor pins at once on the back of the board, then easing the cap out of the board as soon as the joints in the board melt. This causes some of the applied blob to get sucked into the holes in the board, diluting the original lead-free solder and lowering its melting point, after which it becomes possible to get the old solder out with wick and/or a hand sucker.
posted by flabdablet at 3:33 AM on June 10, 2018

Oh, and if you are going to replace them, you can't just stick in any old cap that happens to match the bad one's capacitance and voltage ratings and expect it to work. Mobo capacitors are special low-ESR (equivalent series resistance) types designed to cope with high ripple currents and high operating temperatures. Use high quality parts from a reputable Japanese manufacturer, sourced from a reliable vendor; buying the cheapest "Nichicon" or "Rubycon" caps you can find on eBay is a pretty reliable way to end up with counterfeit garbage parts.
posted by flabdablet at 3:44 AM on June 10, 2018

I know its old and I should probably just get a new one but I really don't want the hassle right now. I work from home so its my work computer so I need to fix it, if it can be fixed. I'm worried the MOBO is dead though (and at that point I might as well get a new one).

There was some good advice in the previous thread about looking into the PSU, and more here about swapping out parts. I'd be looking at the PSU again - if that's faulty then perhaps you've done some damage to the motherboard?

To be honest though, if you've had to use two askmes, hasn't this already caused you more hassle than what's involved in replacing the machine, especially if this is a work rig?
posted by Juso No Thankyou at 4:04 AM on June 10, 2018 [2 favorites]

I have 3 disks, because I did that the last 2 times I got a new computer!

This i s your livelihood. You cannot continually patch it with duct tape and push the problem off until the next disaster, you know?
posted by DarlingBri at 6:08 AM on June 10, 2018

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