Need power supply insight.

[PSU87]

This isn't a thread looking for a solution to a problem, I'm just trying to learn why this solution worked. My PC was freezing up frequently, and wouldn't get passed even formating the hard drive when trying to reinstall windows. I proceeding to testing the memory, the hard drive, and even unplugged all PCI and DVD devices, and just used an external dvd drive.

Got a known good CPU from a friend and installed it and even ran a test on the power supply with a power supply tester and it told me it was good. I was pretty sure it was the motherboard, which I just recently replaced a couple months ago. Before I went through the hassle of sending in the mobo for a replacement I decided to try a new power supply and now my PC is working perfectly.

I'm glad I got the PC working, but my technical curiosity has me wondering why it solved it. Both power supplies are 300w and have a 20 pin and 4 pin molex. And the power supply test told me the faulty one was working. I recently bought this PSU tester so if its not a good unit I might as well return it.

Thanks to anyone who replies and gives me some insight into this issue.

 

[SNGX1275]

Well, I may be wrong, but those PSU testers don't put any load on the unit. They just check to make sure the voltages are acceptable.

So its possible your faulty psu could not deliver the correct voltages at the loads required by your components.

This is just a guess, so if your PSU tester does put a load on the PSU then disregard everything you've just read

 

[howard_hopkinso]

Hello and welcome to Techspot.

SNGX1275 has hit the nail right on the head.

The psu tester doesn`t put the psu under any load and therefore the reading doesn`t necessarily mean the psu is ok.

You should have checked the voltages under load with a programme such as the free Everest or Speedfan programme. This would have given you a good idea of the actual voltages under load.

Obviously, the psu was indeed faulty and that`s why your system works ok with the new psu.

Regards Howard :wave: :wave:

 

[PSU87]

Thanks for the replies guys, and now I know, and knowing is half the battle.

So should I never use the power supply tester, or just use it as a starting point on a psu diagnostic?

 

[SNGX1275]

I wouldn't ever use it in a computer again.

But, you could do what I did with a 'dead' one recently. That is open it up, short the green wire to a ground, then put it in a box, and put some terminals on it, run a few of the wires to terminals so you can get a variety of voltages out of it. Its sort of a project box then, and you can do all sorts of worthless? stuff with it. Not very useful at all if you don't get little kicks out of spinning up little DC motors, or lighting up some LEDs or anything else like that.

 

[howard_hopkinso]

Personally, I`d keep hold of it as it may come in handy at some point. There`s nothing worss than getting rid of something, only to find out at a later date you wished you had kept it lol.

You might find this thread of interest.

Regards Howard