Sign in with
Sign up | Sign in
Your question

What to do when the ON button does nothing

Last response: in Components
Share
November 4, 2006 6:55:48 PM

I recently had BIOS problems after a flash. After determining that the flash went bad, I had a new BIOS chip shipped out to me and installed it. With the bad chip, the power light turned on, but it didn't POST. With the new chip, the power light on the front doesn't even turn on. Normally, I would suspect a faulty PSU, but is there any way the BIOS chip could prevent the unit from powering on at all?

MSI Neo 4 Platinum SLI
Antec Sonata 2 w 450 W Smart Power PSU

More about : button

November 5, 2006 8:16:22 AM

The last time that happend to me my psu had fried my mobo (i am the bringer of doom). Can you test your psu on another board? With me my psu was working (but badly) and my mobo was fried - so no power to anything even thogh the psu was working.

The lesson i learned...always buy active PFC
November 5, 2006 12:00:02 PM

this could be stupid, but when you installed the new bios chip, you may have disconnected some little wires without knowing it. have you checked inside your case if the power wire is still properly connected to the mobo?

*hoping this is the (stupid but costless) problem*
Related resources
November 5, 2006 12:50:03 PM

I was wondering the same thing, but since he is able to R2 a bios chip, I would think somthing as simple as a power wire would not be overlooked, just never know though.

wes
November 5, 2006 1:01:06 PM

Quote:
I was wondering the same thing, but since he is able to R2 a bios chip, I would think somthing as simple as a power wire would not be overlooked


yeah you got a point there :) 
but even the smartest people make silly mistakes (look at me 8) :lol:  )
November 5, 2006 1:32:34 PM

When I turn on the power supply, the LAN light turns on, but the ON button on the front doesn`t cause the fans or the HDD to spin up.

Still_Life : Call me crazy, but if the PSU fried the mobo, why would I want to try it on another one? The next time I have access to the computer (later today), I`ll try it with just a HDD to see if it will spin up. Also, I`m in Canada; does active PFC apply to me? I thought it only applied to European PSUs.

Good try with the power cables being loose; I`ve made my share of silly mistakes. Unfortunatly, this wasn`t one of them. The cables were actually the first thing I checked since the computer had been open for a month while I waited for the rediculous RMA time from MSI.
November 5, 2006 1:36:56 PM

do you have a second PSU?
if you have, try firing your pc up with that one
most likely you have because you are typing a response to us :) 
November 5, 2006 1:43:43 PM

off topic..... but RMA time from MSI is HORRIBLE..... took well over a month to get a 6800GT from them, then the one they sent had artifacts. The second one didn't take as long, they rushed it and payed shipping.... so that was better.

wes
November 5, 2006 1:54:30 PM

Quote:
off topic..... but RMA time from MSI is HORRIBLE..... took well over a month to get a 6800GT from them, then the one they sent had artifacts. The second one didn't take as long, they rushed it and payed shipping.... so that was better.

wes


totally agree
MSI just sucks totally. i once had a mobo from msi (no, don't ask witch one because i don't want to remember it...) and it died in one month. had to wait
four months to get a new one.
November 5, 2006 3:34:30 PM

Quote:
When I turn on the power supply, the LAN light turns on, but the ON button on the front doesn`t cause the fans or the HDD to spin up.

Still_Life : Call me crazy, but if the PSU fried the mobo, why would I want to try it on another one? The next time I have access to the computer (later today), I`ll try it with just a HDD to see if it will spin up. Also, I`m in Canada; does active PFC apply to me? I thought it only applied to European PSUs.

Good try with the power cables being loose; I`ve made my share of silly mistakes. Unfortunatly, this wasn`t one of them. The cables were actually the first thing I checked since the computer had been open for a month while I waited for the rediculous RMA time from MSI.


The best thing I can suggest is to disconnect everything from the psu except for a couple of fans and maybe an optical drive (cheap components) and short the green (#14) and any black wire on the 20/24 psu to mb connection.

PFC (Power Factor Correction), is required in Europe (by law) but that doesn't mean that we don't benefit from it everywhere else. Active PFC, regulates the power and distributes it correctly to prevent "dirty" or erratic AC power from reaching our DC powered parts.
Anonymous
a b ) Power supply
November 5, 2006 5:28:21 PM

I would try shorting the 2 Power On pins with a screw driver. Something as stupid as a broken power button can take time to troubleshoot...who knows =)
November 5, 2006 10:40:32 PM

Well, I tried shorting the power on pins on the mobo and that did the same thing as the ON button on the case: absolutly nothing. Then I shorted the On wire to ground on the mobo to PSU connector. With 2 fans, the front LED and 2 DVD drives connected, the fans spun and the LED turned on, but the DVD drives were not responsive. This is looking more and more like a dead PSU, but it had absolutly no problems until the BIOS chip when bad, so it seems like too much of a coincidence. Any way the firmware in the DVD drives could require the ATA connector (ie the mb) to have power in order to open?

PS. My other PSU is the only one I have left and it's a few years old. I'm not sure it has the required connectors for my mb and I don't want to chance it being killed by whatever the problem is. Two dead computers would suck even more than one.
November 6, 2006 5:26:11 AM

Yea it sounds like the PSU is dead. You can check that by testing the PSU independently from the motherboard / cpu / gpu by removing those respective connectors, connecting some hdd / dvd / cd drives / fans then "jump start" the PSU by simulating the "power_on" motherboard signal by shunting the "PS_ON" green wire to ground via a paper clip or something - then plugging the unit in and powering the rear switch on...

Here is an example of the atx jumper:



It should fire up the PSU and stay on, the drives should be spinning and the cd/dvd should be able to eject. You *have* to have at least one hdd or cd/dvd drive connected to act as a "pull-up" load to power the unit on. If you have a voltmeter you can test voltages. If the PSU can't stay on it's probably bad.

Quote:
Active PFC, regulates the power and distributes it correctly to prevent "dirty" or erratic AC power from reaching our DC powered parts.

I cringed when I read that, it's a common misconception / myth about PFC. That specific function is a job that power conditoners and UPS systems with automatic voltage regulation perform, not PFC. PFC is all about reducing the amount of reactance your SMPS creates from being seen by the remainder of your AC network.

Quote:
SPCR"]Power Factor Correction (PFC) can be defined as the reduction of the harmonic content, and/or the aligning of the phase angle of incoming current so that it is in phase with the line voltage. Mathematically, Power Factor (PF) is equal to Real Power (Watts) divided by Apparent Power (Volt*Ampere). The basic concept is to make the input look like a pure resistor. Resistors have a power factor of 1 (unity). This allows the power distribution system to operate at maximum efficiency, which reduces energy consumption.
[/url]

So adding an active PFC PSU to your PC will not hurt your existing power factor. It definitly will not help to clean up dirty AC power that is pre-existing. When wifey fires up her arcwelder to fix her quadrunner's cracked frame, and it creates a low-voltage environment (brownout) for anything over 16-20ms your pc may feel it and crash. Unless you have a UPS system with AVR function, that is :wink:
November 6, 2006 11:45:17 AM

After you shorted the wires did you check voltages? If those are off, then you know its the PSU. I'm fairly certain a DVD drive doesn't need the ATA cable to open, but it's been a long time since I troubleshooted anything like that.
November 6, 2006 9:37:19 PM

Thanks for the help so far. I talked to someone at the local computer shop today and he assured me that I could connect the 24 pin to the mb without the 4 pin and that it wouldn't damage anything. However, I wanted to confirm that since this guy had never heard of Seasonic. If it turns out that this is ok to do, I'll try my older PSU and that should give me a definative answer, or the closest I can come to one since my multimeter died in a horrible flood - a story for another post!
November 7, 2006 11:23:54 AM

I have the Antec Sonata II case as well and one day it just wouldn't turn on. Flipped the switch in the back on and off and nothing. Thought the PSU was dead and started researching the web. Lots of people having the same problem with these power supplies and Antec is replacing them if you have a problem.

However, I discovered that if I cut power at the back PSU switch for 10 seconds, then it powers up at the front switch with no problems. This happens everyday. It's a pain but I can't be without this system and haven't had time to troubleshoot further. I think there is a problem with these power supplies holding current and not recognizing enough of the short on those jumpers to signal a power on. Just a theory. But I've also had MSI boards act really flaky when BIOS was changed too. ie. not starting up when I hit power. So you've got a couple of culprits.
!