Kind of a long storey but my computer started shutting down this week. At first i thought it was a software issue but finally let it just sit on the bios screen to separate hardware from software. It shut down after about 12 hr. So now i figure hardware. I have pulled everything from the motherboard so I’m just down to motherboard, cpu, ssd, memory and known working power supply, mouse, keyboard, monitor. It still is shutting down and some times won’t boot at all. So it has to be motherboard, cpu, or memory. When it has booted into windows 10 i have a done a short memory test. All temp and fans look ok. My thought is that it’s the motherboard. Any ideas?
I had some RAM that was bad from the factory. It did damn near the same thing. I pulled one stick out at a time to test it.
2 Likes
Did you check the heatsync on the CPU, it might be overheating if something changed causing a gap or thermal paste isn’t sufficient. Overheating would do this.
2 Likes
When it shuts down, does it blue screen and dump memory, or does it just go dark? A blue screen will tell you what offended the system. A black screen will tell you something as well; you have lost the video feed. It’s not the mouse or keyboard, and you can switch monitors easily to eliminate. You can eliminate the video chip by adding a graphics card. You can check the power supply with a voltmeter, to see if 3.3V, 5.0V, or 12V has locked down. You would need an oscilloscope to see the noise level riding the DC voltage.
I have a hunch @themitch22 is on the trail. A bad CPU is the hardest problem you will ever diagnose.
You could also have a cap issue in the power supply causing random shutdowns.
1 Like
If it is 5 or more years old I’d say caps are quite likely, often will look bloated (top will have a dome) instead of outright failure.
1 Like
It just goes black. If i power it back on, it will come back normally (although it’s asking for a password that it normally doesn’t). Then at some point, minutes to hours later, it will go black again. If i boot to the bios page and leave it, it still goes black after a while. I pulled the graphics card and am now using the on board graphics and there is no change in behavior. I pulled a power supply from a working system so it should be ok. I’ve re-seated memory. The motherboard has self check leds that check the cpu, memory, and video before boot. Those go ok except that sometimes even if they all light up, it still won’t boot. This generally happens when I’ve tried to reboot several times. This is a several year old system so cpu pins can’t be the problem. So i thinks it’s heat somewhere, a bad cpu or a bad motherboard. I’ve got a new motherboard coming in case i need it. I’m going to reattach to mb heatsink to check that. If that doesn’t work I’ll reassemble from the motherboard up. Sorry about the typing. I’m down to a tablet for communications.
1 Like
It has to be hardware based if it has the same behavior in BIOS… CMOS battery can also cause weird issues. If it was overheating it would either report that, or not start again at boot, or shut down shortly thereafter. Also, OBGC could be shot.
Either way, if it’s not the CMOS battery, I’d say it’s probably not worth troubleshooting the MB. Just pick up a cheap one and rebuild.
Bring it up to DMS, leave it powered on for a couple hours, then grab our Flir E4 and look over the inside of the case, peering under the heatsinks from the side if you can. If it’s heat related that should show it up pretty easy.
You say you have a known working PSU - how sure are you of that? The behavior doesn’t rule out a PSU problem.
I pulled the power supply (fairly new) from another working pc so it would be really bad luck if both supplies were bad in the same way. I tested the voltages from the broken pc and they are fine at least with the info this little tester gives me.
I replaced the cmos as one of my first steps. What’s obgc?
Edit: Cmos battery
Yesterday morning i re-seated the power supply connections, disconnect the front panel lights and switches and reset the bios again. It booted to the bios. I set all the fans to high. I let it sit there for a couple of hours and then booted into windows. I ran several stress tests on it and never got an error and nothing over heated. I checked all over the board with a non contact thermal tester and nothing was hot. It’s still running this morning, so i may or may not have fixed something. At this point i can either run more test on it or start adding back components one at a time. I do have a new motherboard i could install. It’s very frustrating not to know if it is fixed or if it is, what i did to fix it.
Sounds like a bad power supply or improperly installed processor cooler (loose or no thermal compound).
1 Like
I really don’t think it the power supply but I’ve got one more i can try it with. I really don’t think it’s cpu paste because I’ve run a cpu tester (HeavyLoad) for an hour and the cpu temps run from around 30 at idle to low 60’s at full load.
I’ve got a new motherboard so i think I’ll just build it back. I’ll find out about thermal paste then.
It’s frustrating because it ran for over 30 hours yesterday and today and died an hour ago. Other times it has only run a few minutes before dying.
on board graphics card. that may be the wrong acronym, I’m sorry.