Power Supply Pinout +5VDC

[Botard]

Good day, I got a reading 4.65V. Shall I buy a new power supply? I have found from internet the 5VDC pin has +/- 5% tolerance, which 4.75~5.25V its range.

Thanks.

 

[TechnoMage2016]

AS a Computer Tech, I'd say that if you can afford a new PSU, and you can easily buy one, do so, as soon as possible.
That 5v line is critical, because it drives all of the electronics in your PC. If it's sagging, that can cause all sorts of problems.

If that is an original supply, it can also be just barely strong enough to power your PC, so opt for a much stronger PSU.

I won't even waste my money on any replacement PSU that is not at least 400 Watts. One with two 12v rails is also a good idea, if you can get one.

Just for safety, my personal PC has a 650 Watt PSU, with dual 12v rails.

Good Luck, Mate!
TechnoMage

 

[Mellon Head]

Good day, I got a reading 4.65V. Shall I buy a new power supply? I have found from internet the 5VDC pin has +/- 5% tolerance, which 4.75~5.25V its range.

Thanks.

What are you using to read the voltage on the 5V rail? A software program, or a digital multi-meter?

Software programs reading voltages are notoriously error prone. Even BIOS won't give you an accurate reading. Before investing in a new power supply, measure the 5V and 12V rails with a proper electrical meter. And by proper meter, I mean something like this:




If you don't get 5V and 12V +/- 5%, then do as TechnoMage2016 says and replace your PSU with a quality model. Seasonic and Corsair both make good quality PSUs. Remember that a good power supply is fairly expensive, but it's worth it. It is the heart of your rig, and it's the very last component that you should decide to be cheap about.

 

[Botard]

AS a Computer Tech, I'd say that if you can afford a new PSU, and you can easily buy one, do so, as soon as possible.

It's been running for a year, I hope no other parts affected.

That 5v line is critical, because it drives all of the electronics in your PC. If it's sagging, that can cause all sorts of problems.

PC monitor went black while system unit kept running, sometimes it restarted when tried windows multitasking, getting worse nowadays.

If that is an original supply, it can also be just barely strong enough to power your PC, so opt for a much stronger PSU.

Yes, it's original power supply a 500W dual 12V rails.

What are you using to read the voltage on the 5V rail? A software program, or a digital multi-meter?

A digital multi-meter. All 5V rails were read 5.01V except one rail 4.65V outside the range. The +12V rails look fine as well as the 3.3V rails, while -12V rail (+/-10%) reads eleven point something, voltage.

Seasonic and Corsair both make good quality PSUs. Remember that a good power supply is fairly expensive, but it's worth it. It is the heart of your rig, and it's the very last component that you should decide to be cheap about.

I think I have to wait days to get a quality...

 

[Botard]

By the way mates, does anyone have experienced troubleshooting a power supply, like this one I got critical voltage below wondering has a bad capacitor needs to replace? I have some traditional tools for repair want to use some spare before consider to buy a new one.

 

[Mellon Head]

As someone who frequently designs that type of power supply for other purposes, I would strongly advise against opening and messing about in that power supply. They are complicated to troubleshoot and repair, and the resulting repair could fail, damaging your system or starting a fire.

Best to simply replace it if it's not working right.

 

[TechnoMage2016]

Being a 'Board Level' repair tech, I HAVE replaced bulging capacitors in a PSU, but it's not easy. And finding High Quality replacement caps is also not the easiest thing to do.
I'd not recommend it for anyone but a professional.

I repaired one (cheap) PSU, just to see if I could. I'd already re-caped several motherboards with great success. But it's very tedious and exacting work, and some special tools are required, when working on Multi-Layer printed circuit boards.

When I get a failed PSU, I always open it up, to see what failed and it's almost always a case of Cheap Chinese capacitors that are bulging and leaking. That can cause other parts to fail as well. I'll save the fan and toss the rest.

Good Luck Mate!

 

[Botard]

Strong advise noted and thank you. I feel confident to hear impressive experience from tech. Theoretically, the 5VDC rail is just a design giving a regulated output from 220/115V unstable input. Also, replacing any components need to check their data sheet, failing that specification might burn the component itself due to heating effect, as I remembered. You must have a higher income for motherboard repair.

 

[mjf]

PSU capacitors can store lethal voltages for some time after the PSU has been disconnected. Unless you know exactly what you are doing I suggest you don't attempt any repairs. You don't need to go 80 Plus Platinum for a new PSU. If money is tight you can still get a name brand at a relatively low cost.

 

[fireberd]

I'm an old time electronics tech (I used to have ham and commercial FCC Radiotelephone licenses) and would not recommend attempting any power supply repair. If its defective best to dump it. Everything in the computer is dependent on proper voltages and adequate amperage (power).

 

[Botard]

PSU capacitors can store lethal voltages for some time after the PSU has been disconnected.

Yes, I can discharge it by a few ohms resistance.

Everything in the computer is dependent on proper voltages and adequate amperage (power).

That's the reason should have a data sheet specification.