Power up Problem Fix Q

[Justintoxicated]

I have the problem where if I push the Power button to turn off my computer I can't boot back up without shutting the power supply off and then back on. And I am tired of climbing under my desk)

 

Any other time (resetting and shutting down from windows) I do not have this problem.

 

I went out and got a 22uf cap, then realized im supposed to get a .22uf cap..

 

Went back to radioshack and realized they don't have any .22uf in stock (the only one they are out of lucky me)

 

So will the 22 micro farad cap work or will it cause problems?

[Justintoxicated]

I have now been to several Radioshacks and I cannot find a .22uf capacitor.

 

Anyone know if the one I have will work?

[frenchie]

Probably not. You won't hurt anything by trying it though. Just order the right one from mouser. With shipping its probably not much more expensive than the radio shack one:

 

http://www.mouser.com/?D=140-PF2A224J&hand...4J&crc=true&N=0

 

...or ask RS to order it for you.

[staffypup]

>Probably not. You won't hurt anything by trying it though.

I strongly disagree. If it is 22uf it is an electrolytic. Which means it is polarity sensitive. If these devices are connected with the polarity reversed, they usually explode, covering everything with dessicated aluminium foil. Not too healthy for the insides of a computer.

[Kirby Smith]

The goal here is to filter short transients. It is unlikely that the value 0.22 uF was determined by simulation and analysis, and it is even more unlikely that the value must be precise.. If you can't find a 0.22 uF, buy two 0.1 uF caps and put them in parallel. Use them temporarily if desired until the more elegant solution of a single 0.22 uF cap is available.

 

And no, don't use electrolytics unless you want to delve into the circuit characteristics a lot deeper. They might have to be bypassed anyway with a smaller cap due to high ESR at higher frequencies.

 

From what I've read here, this problem appears to be a PSU design oversight -- not anticipating noise on the control line.

 

kirby

[KeTeFLiPs]

I have the same problem. let us wait for a solution:)

[Justintoxicated]

so Enermax Liberty 620 watt is crap? This PSU cost me a fortune. I'm going to call enermax and see if they will cross ship me a new unit, if not I guess that I just wasted $200.

 

Funny how they work fine on other motherboards....

 

I hate getting the run aorund from manufacturers, Enermax is going to tell me it is my MB and DFI of course will tell me it is the PSU...

[Frog Hunter]

I had same prolem and when I changed cases it went away.

[Prostock62]

I just went to power up my computer with a expert board and it would not power up.I had to shut the power off at the surge protector then it would power up.This sounds like the same problem.Ive had this board for 3 weeks now with no problems until now.Ran fine powered up all the time.Now this and the temp not reading correct.Leave a perfect nf4 sli-dr for this crap.No changes.I found this to be corrected by bios change on my board.Some bios have the problem and some dont.The 7042bta i can not run,when i flash to them after cmos clear the system just keeps rebooting over and over.The 04/06 bios no issues.

[Hawk454]

Break out a multi-meter and test for the PS_On signal. If present then it is not the PSU. Power supplies have a simple on/off/stanby function that is controlled by the motherboard. The motherboard has the function of maintaining the status to tell the power supply.

 

By checking the PS_On signal pin you can determine which assembly is causing the error for sure. The motherboard will allow the path to be connected to enable the PS_On signal to go high and within 1/2 second max the voltage rails should be at optimum. If this does not occur, then disable the PSU from the motherboard and try to jumper (paperclip or male pin works to short the green wire to a black wire) the connector to manually turn on the powersupply. Use a switch inline with the short created to turn on/off/on to verify the powersupply can recover after being shutdown.

 

This error is far more likely to occur from the motherboard than the power supply. However if the powersupply does not send a power ok signal in time then the motherboard will not power up. Or if a voltage was over or under during operation the Power supply can apply protection that will stay in effect after a soft shutdown occurs.

 

Some links:

http://www.formfactors.org/developer%5Cspe...X12V_PS_1_1.pdf

http://www.enermax.com.tw/english/upload/d...16334895923.pdf

 

PS. IF you believe it to be the power supply, then use paragraph 3.3.7 of the ATX Power Supply form factor requirements guide as backup for an immediate RMA for repair or replacement.

[Justintoxicated]

The problem is that I can not wait 2 months for an RMA as I need this computer NOW, I didn't buy the most expensive motherboard available, to wait anotehr 2 months to get working parts... I Played this game before with Nvidia and I refuse to play it again with DFI, or anyone else. I would have to just fork out another $200 for a different MB.

 

Wait 2 months for an RMA, that is just ludacris....Does it really take that long?

 

Since the problem ONLY happens from a Hard Shutdown (if I shut down from windows it restarts EVERY time) would this indicate alone that it is a Motherboard or PSU problem specificaly without having to splice into the PSU's wiring to test with my DMM? I will see if I can find the documentation on how to locate these pins etc, but may not have time to take apart my PC for testing any time soon.

 

I have already verified the PSU can be powered on and off (using the switch on the back of it, while jumpered) I had to do this to test my liquid cooling loop. but I did not put a switch inline with it, I should use a PC switch correct? I'm a little worried about killing the switch on my $180 case.

 

Thanks for the info.

[frenchie]

Since the problem ONLY happens from a Hard Shutdown (if I shut down from windows it restarts EVERY time)

 

I don't understand why that would be a problem worth RMAing for. How often are you planning on doing a "Hard Shutdown"? The only real reason to do it is if you crash in which case it doesn't seem like too much trouble to cycle the PSU. I doubt very much that the RMA fix addresses your problem anyway as the problematic "cold boot issue" occurs after a proper shutdown procedure (not after suddenly turning off the power - which is bad).

 

You don't need to splice or open up your PSU in order to test it with a DMM. You can plug the DMM into the molex connectors. I don't understand your question about a PC switch. If your PSU is booting though and you have windows installed, why do you think there is a problem with the PSU? You have totally confused me. It sounds like your PSU is probably fine though.