Question A PC died on me out of the blue and I don't have an obvious culprit

Feb 20, 2020
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Hi all. So, I found a PC lying on the street a few days ago, and it was fully working to my surprise. Neat. It has a Pentium D 2.8Ghz processor, an NVIDIA GeForce 7600 GS, two sticks of 512MB of RAM, and another two sticks of 2GB each for a total of 5GB of RAM. These are not the best specs as you can see, but they ain't bad if it's free. So, I thought about retrogaming. I tried a couple of retrogaming OS like Lakka and recalbox and none worked, my guess is driver incompatibility with the GPU, until I tried Batocera Linux, that one seemed to do it. It worked fine, played some games, until today when I launched Crash Team Racing and the game completely froze in place, the audio got stuck and started glitching out, and a few seconds later the display showed a "no signal" message. "Oh <Mod Edit>" I thought, something really bad just happened.

So, this is where my troubles began. After the incident, the PC doesn't even boot or display anything on screen. I turn it on, fans start spinning but I don't hear the usual boot beep from the MB speaker, then a few seconds later it shuts down, and restarts by itself to do the same. First of all, no smoke, no smell, nothing seems to have fried, so that's good. I thought about a faulty RAM stick first, so I manually tried them all by swaping them one by one, everything was the same, I even cleaned the contacts with alcohol, nothing, RAM doesn't seem to be an issue here. Soooo then I thought about the CPU. I tried to turn on the PC without cooler, and it quickly burned like crazy, so it seems to be working, or doing something at least.

I also tried to disconnect absolutely everything, preipherals, GPU, disk drives, HDD, fans (except CPU cooler), everything except the PSU, the MB and the CPU. My plan was to try and hear the beep to check that it was booting, but alas, no luck, it did the same thing. I read online that some dude fixed a similar issue by taking out the MB battery, cleaning it a bit with his T-Shirt and putting it back on, so I tried and nothing again. So, I'm kinda out of ideas to be honest, it's such a bummer that it broke, and it's even worse that I don't know how can I diagnose it. I have other PCs available on my house to test it with, in case I need spare parts or something of the sort. I'd love to give you guys the MB model but I don't know it from the top of my head, and I can't check it with software for obvious reasons. What do you guys suggest? Thanks.
 
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Hi all. So, I found a PC lying on the street a few days ago, and it was fully working to my surprise. Neat. It has a Pentium D 2.8Ghz processor, an NVIDIA GeForce 7600 GS, two sticks of 512MB of RAM, and another two sticks of 2GB each for a total of 5GB of RAM. These are not the best specs as you can see, but they ain't bad if it's free. So, I thought about retrogaming. I tried a couple of retrogaming OS like Lakka and recalbox and none worked, my guess is driver incompatibility with the GPU, until I tried Batocera Linux, that one seemed to do it. It worked fine, played some games, until today when I launched Crash Team Racing and the game completely froze in place, the audio got stuck and started glitching out, and a few seconds later the display showed a "no signal" message. "Oh <Mod Edit>" I thought, something really bad just happened.

So, this is where my troubles began. After the incident, the PC doesn't even boot or display anything on screen. I turn it on, fans start spinning but I don't hear the usual boot beep from the MB speaker, then a few seconds later it shuts down, and restarts by itself to do the same. First of all, no smoke, no smell, nothing seems to have fried, so that's good. I thought about a faulty RAM stick first, so I manually tried them all by swaping them one by one, everything was the same, I even cleaned the contacts with alcohol, nothing, RAM doesn't seem to be an issue here. Soooo then I thought about the CPU. I tried to turn on the PC without cooler, and it quickly burned like crazy, so it seems to be working, or doing something at least. I also tried to disconnect absolutely everything, preipherals, GPU, disk drives, HDD, fans (except CPU cooler), everything except the PSU, the MB and the CPU. My plan was to try and hear the beep to check that it was booting, but alas, no luck, it did the same thing. I read online that some dude fixed a similar issue by taking out the MB battery, cleaning it a bit with his T-Shirt and putting it back on, so I tried and nothing again. So, I'm kinda out of ideas to be honest, it's such a bummer that it broke, and it's even worse that I don't know how can I diagnose it. I have other PCs available on my house to test it with, in case I need spare parts or something of the sort. I'd love to give you guys the MB model but I don't know it from the top of my head, and I can't check it with software for obvious reasons. What do you guys suggest? Thanks.
With such old PC I would suspect PSU first.
 
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Reactions: helpstar
Feb 20, 2020
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Check the PSU for bloated capacitors
No need, I just replaced it entirwly with the one on my main rig, which I know works 100%, does the same thing. Although these last few times it doean't restart, it doesn't post or send any signal to the monitor, but it keeps running.
 
So I don't think it is the capacitor. I've actually seen systems with ones worse than that keep running. :oops:

So I'm all about you saving that system as it was working fine just a bit ago.

First of all, I would try removing the gpu if it has some sort of integrated graphics. Try it booting that way. Even if it doesn't have integrated graphics I would try it and see if you get any beep codes.

Next, I would put a fresh cmos battery and see what that does. Stranger things have happened if it fixes it...

After that the next thing I would do is unplug it completely and let it sit like that for at least 24hrs. Because that's basically how it was sitting when you found it right? Then plug it back up and see if it works. If so, then you've got an intermittent problem to chase down. But no worries because we can find it!
 
Feb 20, 2020
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So I don't think it is the capacitor. I've actually seen systems with ones worse than that keep running. :oops:

So I'm all about you saving that system as it was working fine just a bit ago.

First of all, I would try removing the gpu if it has some sort of integrated graphics. Try it booting that way. Even if it doesn't have integrated graphics I would try it and see if you get any beep codes.

Next, I would put a fresh cmos battery and see what that does. Stranger things have happened if it fixes it...

After that the next thing I would do is unplug it completely and let it sit like that for at least 24hrs. Because that's basically how it was sitting when you found it right? Then plug it back up and see if it works. If so, then you've got an intermittent problem to chase down. But no worries because we can find it!
Well, I had already done the GPU thing to try and hear a beep, I don't think it has an integrated GPU as I can't see a display output connector on the motherboard, at least none that I know or have, but that didn't work either. I don't have a replacement battery but I'll try it with the one from another PC. If not, then I'll try to leave it naked for 24 hours, but to my understanding this would only help to purge RAM and other volatile memories right? Anyways I'll have to try these options tomorrow, thanks for the suggestions I'll report back.
 

grimfox

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Jun 2, 2009
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Leaving it unplugged for 30 seconds should be enough to purge the ram completely. Leaving it unplugged for 24 hours should allow the PSU capacitors to discharge substantially. (but could still pose a risk if you take the psu apart. Never assume a capacitor is discharged.) Unplugging and pressing/holding the power button a few times will help dissipate energy from those caps.

If you aren't inclined to use a soldering iron on this board then disregard the next paragraph.

That cap you found on the MOBO is definitely slightly bloated. The top should be completely flat. Such that all three pieces reflect light together, yours is not. Thankfully they are easy to source and pretty easy to replace, if you are bold enough. What are the markings on the sides? Two values we're looking for are XXuf and XXV where XX is some number. IE 47uf 16V
 
Feb 20, 2020
27
1
35
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Leaving it unplugged for 30 seconds should be enough to purge the ram completely. Leaving it unplugged for 24 hours should allow the PSU capacitors to discharge substantially. (but could still pose a risk if you take the psu apart. Never assume a capacitor is discharged.) Unplugging and pressing/holding the power button a few times will help dissipate energy from those caps.

If you aren't inclined to use a soldering iron on this board then disregard the next paragraph.

That cap you found on the MOBO is definitely slightly bloated. The top should be completely flat. Such that all three pieces reflect light together, yours is not. Thankfully they are easy to source and pretty easy to replace, if you are bold enough. What are the markings on the sides? Two values we're looking for are XXuf and XXV where XX is some number. IE 47uf 16V
I always wanted to do these kind of repairs, but I don't have the equipment, it's too expensive. By the way I found some more capacitors that are kinda bloated too.
 

grimfox

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Jun 2, 2009
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A soldering iron and some materials are all you need. 40USD on the cheap side. It's a good investment if you are going to make a habit of grabbing computers from the side of the road.

I got my iron second hand. It's a production line grade unit probably 150USD new. But they are pretty robust. Replacement tip and heater cartridges aren't too expensive. Some solder and a flux pen are relatively cheap. It's a rabbit hole but those are the very basics. Solder wick, flush cutters. wires, traces repair, epoxy. There are lots of other little things to buy. But an iron, flux, and some solder are all you need to start.
 
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Feb 20, 2020
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Well, a few days passed with it disconnected from everything, and I tried to turn it on again and the same happens, fans spin but no output or beeps. Sorry to have kept you waiting for so long I was doing other things.
 

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