What shuts down a power supply?

Mel_P · 19 Mar 2006 at 23:07

Hi all,

I had an Antec Phantom 350watt fanless psu installed until yesterday. It's been in 11 months and all has been OK up until now. Yesterday the PC woudn't start up - I pushed the power-on button and the PC burst into life and then died within a second.

It was workng perfectly OK before I shut it down hours before. It normally runs at least 12 hrs /day and quite often 24/7.

I still had the old psu - a Q-Tec 350 watt quiet unit - so I swapped it back. PC started up perfectly Ok. Then swapped Antec back - wouldn't start. Put Q-Tec in - OK. So it seems the Antec has devloped a fault which makes it shut down.

Question - is there one of the cables that senses some voltage that makes it shutdown? Is there any adjustment. Have sent an RMA request to Antec - just wondered if anybody else had the same problem?

Mel_P

Defcon5 · 19 Mar 2006 at 23:20

it may have a safety featur that shuts it off to avoid damaging youir system

Six6siX · 19 Mar 2006 at 23:24

This exact thing happened to me before when I swapped an old Q-tec 550 for an Enermax 465. The surge/short protection in the enermax (and other better quality psu's) was kicking in at boot. The q-tec had none of this protection, hence my machine ran fine with it (but i still wanted it changed..tick tick tick...)

Narrowed it down to my graphics card (radeon 9700 pro all in wonder, at the time) that was pulling too much current at boot up, for some reason.

Not too sure what to suggest as a workaround tbh, but see if unplugging optical/hdds/graphics makes any differece with the antec psu.

Mel_P · 19 Mar 2006 at 23:40

Interesting - thanks.

My graphics board is also an ATI 9700 pro - but if it is that there is nothing that can be changed to stop it?

Also it has worked OK for 11 months and I have added nothing recently.

Six6siX · 19 Mar 2006 at 23:53

I did make a workaround for this problem with the graphics board, and I posted on this forum. Might have been pruned though.

I basically made a variable time delay circuit which allowed 5v and 12v power to get to the external power connector on the card at an adjusted time after you press the power button. This solution has been working fine for many months for me.

I have a full circuit diagram if you are interested.

As for it working without any problems for 11 months, that is very strange.

edit: try starting up without the external power connector on the card plugged in. If it boots correctly, you have found the problem and it should display a message on the screen asking you to turn the computer off and reconnect the power supply.

If not, then something else is havin a laugh..

CurlyWhirly · 20 Mar 2006 at 01:21

Six6siX said:
The surge/short protection in the enermax (and other better quality psu's) was kicking in at boot

That's good to know.
I'm glad I bought an Enermax PSU now :cool:

Mel_P · 20 Mar 2006 at 09:09

Six6siX said:
try starting up without the external power connector on the card plugged in. If it boots correctly, you have found the problem and it should display a message on the screen asking you to turn the computer off and reconnect the power supply.

Do you mean the one of the graphics card?

Mel_P

Six6siX · 20 Mar 2006 at 13:35

Mel_P said:
Do you mean the one of the graphics card?

Mel_P

Yeah, the external power connector on the graphics card. Using your antec supply for the rest of the system, power up with the card disconnected and see if that changes anything.