Question PC doesn't boot. Switches on when button is pressed and switches off right away. Please help.

[theOmkarPatil]

This issue has been happening for a week now.

For the first 5 days, I could just turn off the main power, wait for a minute, retry and the PC would start. But since 2 days, it hasnt been turning on at all.

Following is what I have tried:
• Day before yesterday I unplugged the GPU and the RAMs, and it started in the morning. But had the same issue yesterday.
• Yesterday, I rewired and reseated everything except the CPU and the AIO cooler (I rewired the pump's and fan's power pins though), and the PC started. But I'm facing the same issue again today.
• I tried starting the PC by jumping the pins on the motherboard but it does the same thing as in the video.
• Made sure there's no issue with ground.

Could this be a PSU issue? Or is this some kind of shorting issue? Some folks recommended reseating the CPU as well but if it started without doing that yesterday, I doubt that could be an issue, or am I wrong?

Please help. I work from home, and this is costing me work hours.

 

[Chicano]

The symptoms, I read, are similar to an overheating CPU. At startup is when the computer needs more power, therefore the capacitors pitch in. The CPU may overheat from the increased power during startup, and if that's not the cause, I would suspect of the PSU or bad capacitors.

One more possible cause may be a BIOS setting... the CPU overheating warning may be set to low... this makes the BIOS think the CPU is overheating and shuts off to protect it... BUT you would have to had recently tweaked that setting... and you haven't, have you?

You haven't reseated the CPU (and shouldn't), but have you ever removed it's cooler? and restored the thermal grease coating? Have you checked if the CPU fan is working? Have you tested with a different PSU?

 

[theOmkarPatil]

The symptoms, I read, are similar to an overheating CPU. At startup is when the computer needs more power, therefore the capacitors pitch in. The CPU may overheat from the increased power during startup, and if that's not the cause, I would suspect of the PSU or bad capacitors.

One more possible cause may be a BIOS setting... the CPU overheating warning may be set to low... this makes the BIOS think the CPU is overheating and shuts off to protect it... BUT you would have to had recently tweaked that setting... and you haven't, have you?

You haven't reseated the CPU (and shouldn't), but have you ever removed it's cooler? and restored the thermal grease coating? Have you checked if the CPU fan is working? Have you tested with a different PSU?

Hello, thanks for the response.
For the last few days, when the PC DID boot after this issue, there haven't been any heating issues. I monitored the temps and they were normal.

I haven't touched the BIOS settings since I built the PC in February last year. And I haven't removed the cooler or the fans since then either. Yesterday, I just removed the wires for the coolers and fans, and plugged them back in. The CPU fans are working, I can feel something going on in the pump when I touch it and the radiator fans do work.

I don't have access to another PSU, so I haven't. And here in India, we don't have return policies, only exchange policies on PC components, so I can't really risk the "if its not the PSU, just return it" trick.

 

[Chicano]

Hello, thanks for the response.
For the last few days, when the PC DID boot after this issue, there haven't been any heating issues. I monitored the temps and they were normal.

I haven't touched the BIOS settings since I built the PC in February last year. And I haven't removed the cooler or the fans since then either. Yesterday, I just removed the wires for the coolers and fans, and plugged them back in. The CPU fans are working, I can feel something going on in the pump when I touch it and the radiator fans do work.

I don't have access to another PSU, so I haven't. And here in India, we don't have return policies, only exchange policies on PC components, so I can't really risk the "if its not the PSU, just return it" trick.

You monitored the temps when the computer was running,.. but not when it didn't run!! That makes a difference, it may run when it's not overheating, but couldn't run when it did overheat!! You need to find out what goes on with the coolant pump... What brand and model is the cooler?

 

[theOmkarPatil]

You monitored the temps when the computer was running,.. but not when it didn't run!! That makes a difference, it may run when it's not overheating, but couldn't run when it did overheat!! You need to find out what goes on with the coolant pump... What brand and model is the cooler?

Oh. I didn't think it would heat up within that tiny time frame.

Its a Cooler Master MasterLiquid Lite 240 AIO.

 

[DSzymborski]

The obvious place to start would be a complete list of specs.

And OP, unfortunately, swapping out parts is a basic part of troubleshooting. For a common symptom like this that can literally be nearly anything, there's zero chance anyone can definitively tell you that "X is definitely the problem" or "Y is definitely the problem." You may simply be best served, under these conditions, bringing the PC in to a proper shop and paying them to diagnose the issue, as any reputable one will have plenty of parts to swap in.

 

[theOmkarPatil]

The obvious place to start would be a complete list of specs.

And OP, unfortunately, swapping out parts is a basic part of troubleshooting. For a common symptom like this that can literally be nearly anything, there's zero chance anyone can definitively tell you that "X is definitely the problem" or "Y is definitely the problem." You may simply be best served, under these conditions, bringing the PC in to a proper shop and paying them to diagnose the issue, as any reputable one will have plenty of parts to swap in.

Yeah I figured that would be the last resort.

I'm gonna try reseating the CPU once and if that doesn't work, I'll just go to a professional.

 

[Chicano]

Oh. I didn't think it would heat up within that tiny time frame.

Its a Cooler Master MasterLiquid Lite 240 AIO.

Yes, they do heat up that fast, they don't all give warning messages that I know of, but one computer some 15 years ago, was doing that startup loop, it took maybe 10-12 seconds from start to shut down. And the BIOS displayed a message that said it was overheating, a few seconds before it shut down.

The cooler specifications info says it uses a propylene glycol/water coolant, so what you "feel", could be boiling coolant. But, to boil, it would need empty space, and they should be filled and sealed. A leak would be evident, so there's no certain way of diagnosing it.

 

[theOmkarPatil]

Yes, they do heat up that fast, they don't all give warning messages that I know of, but one computer some 15 years ago, was doing that startup loop, and (I guess the BIOS) displayed a message that said it was overheating, a few seconds before it shut down.

The cooler specifications info says it uses a propylene glycol/water coolant, so what you "feel", could be boiling coolant. But, to boil, it would need empty space, and they should be filled and sealed. A leak would be evident, so there's no certain way of diagnosing it.

So I have now disconnected everything from the motherboard. The CPU is mounted but, I removed its power cable from the motherboard.

RAM, GPU, All fans, Cooler, CPU, SSD, HDD everything is disconnected.

Only thing that it connected to the motherboard now is the huge power supply cable from the PSU (and the CPU that is mounted, without the power source).

I'm starting the motherboard by jumping the pins. And it's still doing the same thing as in the video, except I can make it out by the light on the motherboard. Switches on and goes off right away.

So now I'm confused if this could be a motherboard or a PSU problem.

 

[Chicano]

For the first 5 days, I could just turn off the main power, wait for a minute, retry and the PC would start. But since 2 days, it hasnt been turning on at all.

I didn't pay much attention to this part before... You mean, you had to turn it off... why did you? .. then after a minute, you started it again, and it booted right up?

 

[theOmkarPatil]

I didn't pay much attention to this part before... You mean, you had to turn it off... why did you? .. then after a minute, you started it again, and it booted right up?

Oh no, like I shut the PC off before going to bed every night.

I had the issue from the video in link for 5 days straight. I would turn on the main power (in India, we have buttons for each AC power source), press the button on the cabinet and the thing from the video would happen. But if I tried this after like 5mins again, the PC would start.

But that hasnt worked since Thursday morning. Thursday morning I reseated the RAM and GPU and dusted the components a little, and the PC started.

On Friday morning, the above didn't help, so I reseated and rewired everything except the CPU. And the PC started.

Today, however, none of this is working.
Right now, I have EVERYTHING disconnected from the motherboard. The PSU's HUGE wire is the only thing on the motherboard along with the CPU (but the CPU's power source cable is removed and so is the cooler's), and the PC still won't start.

The light on the motherboard turns on and off similar to how it is in the video.
So now I'm confused if it's a motherboard or a PSU issue.

 

[Chicano]

I missed the video the first time... I thought it had audio and couldn't hear a thinkg online so I downloaded it and still nothing so you didn't record audio just vide.. but it's enough to guess what may be happening. That instant turn off can be caused by the Power switch sticking..

You can reproduce the symptom by bridging the power button contacts on the motherboard with a small screwdriver or appropriate wire or metal object... To start the computer you have to hold the contact for a second, leave it any longer and the computer shuts down... that is what apparently the power button is doing... but, you said it does it even when you "jump start it by jumping the pins on the motherboard", so the problem may be in the PSU or anywhere in the motherboard but I doubt it... maybe if you interrupt the PSU's green wire... cut it, add a couple pairing connectors to the split wire ends so you can connect it again or at least tape it... but split it so you can separate it immediately after switching the computer on... if it stays running, the PSU should be the cause.

Something else you can try, is remove the 24 pin connector from the motherboard, and jump the green wire to the black wire (ground)... power on the PSU and it should stay running just as it would in the PC... if it turns-off, you've got the cause of the whole problem. Right now I have to get some shut eye. I don't doubt you are capable of fixing it yourself.

I included the two links with diagrams to a PC's power on-circuit... I don't have the time to take a good look myself, I have to get some sleep... and you may have solved it by the time I get back here.

PC Start Button Circuit

PC Start Button tracks

 

[theOmkarPatil]

I missed the video the first time... I thought it had audio and couldn't hear a thinkg online so I downloaded it and still nothing so you didn't record audio just vide.. but it's enough to guess what may be happening. That instant turn off can be caused by the Power switch sticking..

You can reproduce the symptom by bridging the power button contacts on the motherboard with a small screwdriver or appropriate wire or metal object... To start the computer you have to hold the contact for a second, leave it any longer and the computer shuts down... that is what apparently the power button is doing... but, you said it does it even when you "jump start it by jumping the pins on the motherboard", so the problem may be in the PSU or anywhere in the motherboard but I doubt it... maybe if you interrupt the PSU's green wire... cut it, add a couple pairing connectors to the split wire ends so you can connect it again or at least tape it... but split it so you can separate it immediately after switching the computer on... if it stays running, the PSU should be the cause.

Something else you can try, is remove the 24 pin connector from the motherboard, and jump the green wire to the black wire (ground)... power on the PSU and it should stay running just as it would in the PC... if it turns-off, you've got the cause of the whole problem. Right now I have to get some shut eye. I don't doubt you are capable of fixing it yourself.

I included the two links with diagrams to a PC's power on-circuit... I don't have the time to take a good look myself, I have to get some sleep... and you may have solved it by the time I get back here.

PC Start Button Circuit

PC Start Button tracks

Hey,
So I've tried a couple things since Saturday.
• I removed ALL components including the processor and the cooler and everything. Only thing connected to the motherboard is the 24pin power cable from the PSU. I jumped the motherboard (touching the pins with a screwdriver) to start it, but something similar to what you see in the video happens - The red light on the motherboard lights up and switches off right away.
• I checked Corsair's website for troubleshooting the PSU, and when I did what they've shown with the 24pin cable and the U-pin, the PSU fan starts and shuts off, exactly as they have mentioned:

• NOTE: Many Corsair PSUs have a zero-RPM feature that results in the fan only spinning for a moment after the PSU is powered on. This still indicates that the PSU is functioning normally.

So now I have to wonder if there's something wrong with the motherboard. Is there like a minimum test I could do to check if the motherboard is okay?

 

[Chicano]

Hey,
So I've tried a couple things since Saturday.
• I removed ALL components including the processor and the cooler and everything. Only thing connected to the motherboard is the 24pin power cable from the PSU. I jumped the motherboard (touching the pins with a screwdriver) to start it, but something similar to what you see in the video happens - The red light on the motherboard lights up and switches off right away.
• I checked Corsair's website for troubleshooting the PSU, and when I did what they've shown with the 24pin cable and the U-pin, the PSU fan starts and shuts off, exactly as they have mentioned:

• NOTE: Many Corsair PSUs have a zero-RPM feature that results in the fan only spinning for a moment after the PSU is powered on. This still indicates that the PSU is functioning normally.

So now I have to wonder if there's something wrong with the motherboard. Is there like a minimum test I could do to check if the motherboard is okay?

Sorry, I don't know if such a tool to independently check the motherboard even exists.
But more hope presents itself. If the isolated and "U" wire bridged PSU only turns off the fan, but keeps running, when connected to the system, the CPU cooler fan should remain running, as well as all the case fans. But all are turning off, right? Then, it seems obvious to me the PSU is turning off.

Confirm that with a voltmeter:
Leave the "U" bridge on, attach a voltmeter to the 24 pin connector; Positive voltmeter wire to either a 12v or 5v connector pin, and the negative voltmeter wire to a black (ground) connector pin.

If the voltmeter registers any voltage above 5 volts, the PSU remains working... No voltage is registered, it's not running.

PC PSU pinout