pc power supply

[gen]

Hello;

This is my first post here.

I have a brand new corsair hx850w desktop power supply, I bought it from someone so it is not under warranty.
From the first time i plugged it in, it didn't start unless I give it a little tab or nudge. I put it in my pc case and used it normally, it worked just fine, and tested the voltages with a multimeter it was very accurate. Sometimes it won't start unless i give it a little tab. After like a month, it won't start with a tab, so i got the psu out of the case and then a tab it worked, but if I flip it over it won't work unless i put it back to the other side.
After 2 days, it won't work whether with a tab or not or putting it on any side.
I took it to an electronics repair shop, he checked it and told me it is still brand new, with no troubles whether in the board or any capacitors, he checked soldering points on the back of the board and the front, but there are no problems. He is trying everyday but can't seem to catch the problem.

So the big question, what do you think the malfunction so i can tell him to check?, because @ that time he is open to all suggestions.

Please help, the psu is still new and it is a waste not to work again.

Thanks for your help in advance.

Regards.

 

[shrtrnd]

Sure sounds to me like your repair guy is checking the right things.
If you bump it and it works, you've got a loose connection somewhere, ....
but you're right, it could be anywhere.
Cold/broken solder joint, broken componet lead, tough to diagnose without looking at
it like your repair guy is doing.
Good luck.

 

[gen]

Hi Shrtrnd;

Thanks for your reply.

Is there a way to jump start the psu other than 24 pin connector, like from the psu board?, because i suspect that 24 pin connector and it's wires may be faulty.

Regards.

 

[(*steve*)]

Take the motherboard in for him to look at.

One possibility is a bad connection on the motherboard where the connector is supposed to be soldered in (and is either not soldered correctly, has a broken or dry solder joint, or damage to the board)

 

[gen]

Hi Steve;

Thanks for your reply.

Well, even if we try to jump start the psu by connecting green + black wires, it won't start.

Regards.

 

[(*steve*)]

Perhaps take a very close look at all the solder connections in the power supply and see if any are dodgy.

 

[Raven Luni]

A problem is worsening without necessarily being aggrivated - reminds me of when my old PC died from capacitor plague. Could it be that?

 

[Sadlercomfort]

It sounds too me like your psu is fine, unless its not providing enough power to all your drives and motherboard, but i doubt this is the case because the 'corsair hx850w' has an excellent output.

Have you checked all the external wires to your drives, or your fans? I say this because PSU's have a safety feature, where if a positive and negative wire touches it wont turn on at all. . but it still provides power to your standby leds, so you don't normally think about this.

I've wired alot of new fans to computers, and have come across this problem before. Best to rule this problem out before worrying about the motherboard.

Ashley,

 

[Rleo6965]

You can isolate if motherboard was causing the problem by installing 2 hardisk only without the mother board. Place jumper wire on dc connector green and black wire.

If problem still the same. Possible cold solder was causing intermittent problem of power supply. You need a magnifying glass to spot the loose solder.

You can also just re-solder all components on the psu board to solve the cold solder problem..

 

[Mongrel Shark]

I had a bad switch a while back. Tested fine, but when you put higher current through, it arcs internally, blows a hole, and goes open circuit. I was able to dissemble and fix my switch. Was very frustrating before I found it. The whole circuit would test ok, even run on the bench, but try and use it, and it would be intermittent, with no apparent reason.