Question Need serious help

[divisor]

Guys please help.

I’ve had my pc now for about a year and a half. i recently moved to indiana and for about a month I have been using my computer fine.

It’s been plugged into a surge protector and i’ve had no problems. now today when I go to start it up, there’s a blank screen and I noticed that the red CPU debug light was on. That was the only thing on, everything else seemed to be working. Ram lighting up, GPU fans were spinning, cooler was spinning aswell. What happened? The night before it was working fine. Also, every single other thing plugged into the surge protector is working just fine as well.

About 30 minutes ago, I was setting up my girlfriends PC to use cause I work in the morning and of course, mine isn’t working. So i’m setting it up and I go plug it into the same surge protector and the same thing happens. The CPU debug light is on but everything else looks like it’s working. I plugged it back into the same power surge cause I didn’t actually think that was the issue! now i’m guessing that it is.


Anyone have this issue and do you guys think this could be fixed? Please help.

 

[helpstar]

Try running without the protector

 

[divisor]

That’s the thing. i tried a separate outlet that’s not even in my room and now the light stays on.

 

[Richj444]

That’s the thing. i tried a separate outlet that’s not even in my room and now the light stays on.

It might be a long shot but try clearing CMOS and see what happens. I have seen that fix a CPU debug issue in the past.

 

[divisor]

Tried that :/ any other ideas?

 

[jasonf2]

Due to the fact that you have had two computers do relatively the same thing in a day or two my suspect would be power quality, paying special attention to the neutral ,ground quality and sag/swells/transients. Losing a ground will mess with your PSUs zero volt reference and cause it to float, while a neutral going in or out will cause voltages to be all over the place and sag/swell/transients will just cause intermittent reboots and instability. While these obviously need to be fixed a good AVR UPS offers significantly better protection than a surge suppressor, they are reasonably priced and while not perfect will protect you from most of what I have listed. If the power quality is really bad a full online UPS with zero switching is really the fix, but they are really expensive and overkill if you have a good psu.

 

[jasonf2]

Also I failed to mention if it is a power quality issue there may be hardware damage as well to both of the units mentioned. I would plug them in at a friends house to see if they fire up.

 

[divisor]

Also I failed to mention if it is a power quality issue there may be hardware damage as well to both of the units mentioned. I would plug them in at a friends house to see if they fire up.

Thank you. If you had to guess what do you think was damaged? Could it be possible the PSU is messed up but has enough power to power everything else, just not the cpu?

 

[jasonf2]

Thank you. If you had to guess what do you think was damaged? Could it be possible the PSU is messed up but has enough power to power everything else, just not the cpu?

There are multiple voltage levels in your computer. There is a 12 volt, 5, and 3.3V DC coming from the power supply and then the motherboard provides the trace paths they need to be for the devices connected. If additional power beyond what the mother board can supply is needed that is when you have additional umbilical's from the PSU for the device. The CPU is fed from the 3.3V and then stepped down to its required Vcore. Because of this the power supply has to be pretty spot on, especially on the 3.3V rail or else the CPU goes unstable with its very low vcore voltage. Other devices that might be pulling on the 12v or 5 volt system for their main power (like fans) will still appear to be working fine with a much wider variance of voltage ripple even with an unstable power supply. If they are being fed directly, as is sometimes the case with fans, they will run whenever the PSU is turned on and will spin even if the computer won't POST.

Before throwing parts at this the first thing I would do is go to a friends and try to plug it in. If it works I would call an electrician to take a look at the power. If not my first guess would be a PSU. Even so I would be checking house voltage and probably throw a $200 AVR UPS before the computer and get rid of your power strip, which in my opinion isn't doing much more for you than splitting out one outlet to multiple ones.

One other trick to try. Unplug the computer and push the power button with it unplugged. Plug it back in and then try to turn it on. Sometimes this will reset the PSU if it has had a low power state lock. If it is a laptop do the same thing after removing the battery.

 

[divisor]

There are multiple voltage levels in your computer. There is a 12 volt, 5, and 3.3V DC coming from the power supply and then the motherboard provides the trace paths they need to be for the devices connected. If additional power beyond what the mother board can supply is needed that is when you have additional umbilical's from the PSU for the device. The CPU is fed from the 3.3V and then stepped down to its required Vcore. Because of this the power supply has to be pretty spot on, especially on the 3.3V rail or else the CPU goes unstable with its very low vcore voltage. Other devices that might be pulling on the 12v or 5 volt system for their main power (like fans) will still appear to be working fine with a much wider variance of voltage ripple even with an unstable power supply. If they are being fed directly, as is sometimes the case with fans, they will run whenever the PSU is turned on and will spin even if the computer won't POST.

Before throwing parts at this the first thing I would do is go to a friends and try to plug it in. If it works I would call an electrician to take a look at the power. If not my first guess would be a PSU. Even so I would be checking house voltage and probably throw a $200 AVR UPS before the computer and get rid of your power strip, which in my opinion isn't doing much more for you than splitting out one outlet to multiple ones.

One other trick to try. Unplug the computer and push the power button with it unplugged. Plug it back in and then try to turn it on. Sometimes this will reset the PSU if it has had a low power state lock. If it is a laptop do the same thing after removing the battery.

Thank you so much, you are so knowledgeable about this. So I understand that the computer runs on different voltage levels now and it
makes sense why the CPU is unstable. is there anyway to test if the PSU is the culprit and that it’s just not supplying the correct voltage?

Also, I just took my pc out into the garage and I plugged it in out there and the CPU debug light was still on. the Garage is running on a different breaker box than what my condo is running on. So I guess it’s not that?

I have tried that trick when I took out the cmos battery to reset.

Could it be possible I could try some fixes on the pc and then take it back out to the garage to see if it will fix itself?

I was thinking of completely uninstalling and reinstalling all the components as if I was building it from scratch again. As well as resetting the cmos again and maybe troubleshooting my ram one stick and one slot at a time to see if the ram
could be faulty.

Do you think I should try this?

 

[jasonf2]

Thank you so much, you are so knowledgeable about this. So I understand that the computer runs on different voltage levels now and it
makes sense why the CPU is unstable. is there anyway to test if the PSU is the culprit and that it’s just not supplying the correct voltage?

Also, I just took my pc out into the garage and I plugged it in out there and the CPU debug light was still on. the Garage is running on a different breaker box than what my condo is running on. So I guess it’s not that?

I have tried that trick when I took out the cmos battery to reset.

Could it be possible I could try some fixes on the pc and then take it back out to the garage to see if it will fix itself?

I was thinking of completely uninstalling and reinstalling all the components as if I was building it from scratch again. As well as resetting the cmos again and maybe troubleshooting my ram one stick and one slot at a time to see if the ram
could be faulty.

Do you think I should try this?

I don't think you are going to hurt anything by going through this process and maybe you get lucky. (And luck helps a lot when trying to hack your way through a pc repair.) Testing the PSU, while it can be done, requires some test equipment that the average person doesn't have. You can use a quality multimeter but I really prefer a calibrated scope under load. Even then I typically will swap with a known good unit and test because breaking out the pin sets can be more work than it is worth. If you don't have a spare psu that is pretty difficult without just going out and buying a new one. If you don't have any expertise in this type of thing a computer repair shop isn't a terrible idea in these cases because the cost of guessing which part is bad, buying the part and trying it and moving to the next possible part adds up pretty quickly where they will have test equipment and spare parts to swap and try.

 

[divisor]

I don't think you are going to hurt anything by going through this process and maybe you get lucky. (And luck helps a lot when trying to hack your way through a pc repair.) Testing the PSU, while it can be done, requires some test equipment that the average person doesn't have. You can use a quality multimeter but I really prefer a calibrated scope under load. Even then I typically will swap with a known good unit and test because breaking out the pin sets can be more work than it is worth. If you don't have a spare psu that is pretty difficult without just going out and buying a new one. If you don't have any expertise in this type of thing a computer repair shop isn't a terrible idea in these cases because the cost of guessing which part is bad, buying the part and trying it and moving to the next possible part adds up pretty quickly where they will have test equipment and spare parts to swap and try.

Alright thank you so much for your help
man. i’m gonna undo everything and put it all together and see if that helps. if not i’ll find an extra PSU that i can borrow from a friend maybe and see if that works. I’ll update you and let you know.

 

[Misgar]

@jasonf2. Modern CPUs derive their power from the +12V EPS 4-way or 8-way connector(s), not the 3.3V rail in the 20/24way ATX connector.

The currents involved to power an i9-13900K up to 250W would be excessive from a 3.3V rail. If we ignore overheads in the VRMs and losses elsewhere, you'd have to supply 75A on the 3.3V rail versus 21A on the EPS 12V rail to run a 13900K at 250W.

I have a sneaking suspicion the 3.3V rail was used to power the CPU in old computers fitted with an AT (not ATX) PSU. I could dig out an old 80486 system in the garage to confirm.

 

[Misgar]

@jasonf2 I'm not sure if I entirely agree with "Losing a ground will mess with your PSUs zero volt reference and cause it to float".

Floating in its own right is not a bad thing. Many power supplies "float", but losing the mains earth connection to an ATX PSU makes it a potential safety hazard (dangerous) for anyone touching the computer if an internal fault occurs. The mains earth is designed to route fault currents safely down to ground (earth) until an inline fuse or circuit breaker trips. Faults might include failure of insulation or components inside the PSU, resulting in high voltage circuits being connected to the PSU chassis. If it's not earthed, you could die.

Switched mode power supplies for computers can function quite happily without an mains earth. Witness the fact that many laptop power supplies come with a Figure-of-8 mains lead with only two wires (Line and Neutral). These "double isolated" power supplies do not need a mains earth, because the step down transformer inside (from mains voltage to SELV) is designed with two layers of insolation, i.e. enamelled Cu wire (one layer) and separate compartments on the transformer bobbin (second layer) for the primary and secondary windings.

Getting back to the OP's problem, I'm suspicious of his "surge protector". If you read a few of the discussions in the link below, you'll find differences of opinion regarding these devices.

https://www.quora.com/Does-the-surg...g-damaged-by-an-unstable-power-supply?share=1

I don't use cheap "surge protectors", preferring instead to plug my computer systems into unsuppressed power strips connected directly to the wall or via a 1500VA APC UPS to guard against power cuts.

Some people surge protectors are a good idea. After all, if it says on the box this $20 strip will protect my computer against all spikes and surges forever, it must be good.

Cheap surge protectors use MOVs which slowly (or rapidly) degrade when subjected to large voltage spikes.

If protectors don't contain additional series components (dual wound chokes) they won't be able to suppress current surges.

When an ATX PSU switches on, it momentarily pulls between 20A and 110A from the mains. You can confirm this by looking at any Tom's Hardare PSU review. These current surges are perfectly normal, but can slowly degrade any mains on/off switches, in line fuses and miniature circuit breakers associated with the ATX PSU.

If you have an electrically "noisy" device in your house, e.g. washing machine, fridge/freezer, ACU, it might be worth investing in an industrial mains filter similar to the one below, to suppress the noise at source.

From the OP's description, both computers suffered damage when connected up in his new home. Both computers were working fine in other locations.

I think he would be wise to dump the surge protector in the bin and ask a professional electrician to check the house wiring.

Then, he can get around to troubleshooting and replacing suspect components I wish him success.

 

[jasonf2]

@jasonf2 I'm not sure if I entirely agree with "Losing a ground will mess with your PSUs zero volt reference and cause it to float".

Floating in its own right is not a bad thing. Many power supplies "float", but losing the mains earth connection to an ATX PSU makes it a potential safety hazard (dangerous) for anyone touching the computer if an internal fault occurs. The mains earth is designed to route fault currents safely down to ground (earth) until an inline fuse or circuit breaker trips. Faults might include failure of insulation or components inside the PSU, resulting in high voltage circuits being connected to the PSU chassis. If it's not earthed, you could die.

Switched mode power supplies for computers can function quite happily without an mains earth. Witness the fact that many laptop power supplies come with a Figure-of-8 mains lead with only two wires (Line and Neutral). These "double isolated" power supplies do not need a mains earth, because the step down transformer inside (from mains voltage to SELV) is designed with two layers of insolation, i.e. enamelled Cu wire (one layer) and separate compartments on the transformer bobbin (second layer) for the primary and secondary windings.

Getting back to the OP's problem, I'm suspicious of his "surge protector". If you read a few of the discussions in the link below, you'll find differences of opinion regarding these devices.

https://www.quora.com/Does-the-surg...g-damaged-by-an-unstable-power-supply?share=1

I don't use cheap "surge protectors", preferring instead to plug my computer systems into unsuppressed power strips connected directly to the wall or via a 1500VA APC UPS to guard against power cuts.

Some people surge protectors are a good idea. After all, if it says on the box this $20 strip will protect my computer against all spikes and surges forever, it must be good.

Cheap surge protectors use MOVs which slowly (or rapidly) degrade when subjected to large voltage spikes.

If protectors don't contain additional series components (dual wound chokes) they won't be able to suppress current surges.

When an ATX PSU switches on, it momentarily pulls between 20A and 110A from the mains. You can confirm this by looking at any Tom's Hardare PSU review. These current surges are perfectly normal, but can slowly degrade any mains on/off switches, in line fuses and miniature circuit breakers associated with the ATX PSU.

If you have an electrically "noisy" device in your house, e.g. washing machine, fridge/freezer, ACU, it might be worth investing in an industrial mains filter similar to the one below, to suppress the noise at source.

From the OP's description, both computers suffered damage when connected up in his new home. Both computers were working fine in other locations.

I think he would be wise to dump the surge protector in the bin and ask a professional electrician to check the house wiring.

Then, he can get around to troubleshooting and replacing suspect components I wish him success.

Sorry on the 3.3v comment. I deal more with industrial components that utilize the 3.3v for cpu power all of the time, but they are low wattage, battle hardened components. Regardless the cpu still runs at something closer to a 1.5v vcore and the psu cannot be moving around for it to be stable. Zero volt reference is very important for voltage regulators and switching power supplies regardless if your design utilizes a battery or wall plug. The battery reference just doesn't need a ground to work.