When PowerSupply button is pressed computer turns on

HELP!
I just placed a AMD Anthlon in a case, and for the first couple of boots the thing ran correctly. There was a problem with the A: Drive so I swaped it with another. Now whenever I turn on the Power Switch from the back of the machien the computer turns on. There is no output to the monitor. I hear the HD power up and the CDRom turns on, but that's it. No beeps, dings. sparks...nothing. Something that was wierd after a while I thought maybe it was the powersupply so I pulled another power supply from another box and used it. First time it worked...I had to press the computer power button to turn it on. Unfortunately I didn't have the video card installed to see if it outputted. I secured everything then went to turn on the PowerSupply power and again the same thing happened with the new power supply. I've never seen this before and I'm about the snap. I know the MB works cuz I just pulled out out of another box that I upgraded. I tried plugging in the MB back to the old Power Supply and the same things happens.

Here's the thing...I bought off of Ubid a case that had a 300 watt power supply...the one I bid on said it was an ATX case. When I got hte case in it said on the box P4 Case. I hope that doesn't make any difference.

Please help...
Jayday97
[email protected]

 

Have you tried a different video card?

 

You might want to re-check your LED connections, especially the one to your power button. Re-seat your RAM and any PCI cards while you're in there as well.

Also, as far as I know, most MB are ATX these days and I've read that AMD and Intel can be fickle about approved power supplies.

 

At this point I have the mb completely out of the case, and the only thing plug'd in is the LED for the power switch...RAM, cards, ect are all out. Still the fans on the cpu turn on once the power is turned on.

I also tried using the same power supply from my old case and the same thing happens.

 

It sounds like you're on the right track to troubleshoot this system. You might try adding on thing at a time until you either get something that works or tells you that it doesn't. (beep codes) Which reminds me; make sure the onboard system speaker is connected.

And, like Angel said, a different or known good video card might be helpful.

PS: Try not to get frustrated. If you work on or with these puppies long enough, you learn how to deal with heartbreak. I keep large hammers in a locked closet during these times.

 

Well, if everything is off of the motherboard except the CPU,CPU Fan, and the LED for MB Power switch...but the problem still persists...is it a problem with the MB? (fried?)

I'm usually excellent in troubleshooting hardware problems...but once i get to the point where the only thing left is the powersupply, MB, and CPU and it still doesn't work I feel as though I have to give it the final gravity test from a 10 story building.

BTW: Thanks for all your help...

[email protected]

 

Hi again, Jayday.

I’m reviewing your situation and have a few suggestions. First, put the MB back in using the known good power supply for that MB and install the basics, i.e.; the RAM and the video card, then make sure your in-box speaker is hooked up so that you can hear any beep codes. Also, make sure that your MB isn’t grounding out somewhere. Double check the LED connections using your manual. It’s very easy to be off one pin or to read the manual in reverse. Connect your keyboard and if you like, the mouse.

Let’s see if this isn’t a software problem rather than a hardware problem before we jump to any conclusions.

Yes, your MB may be toast but let’s not count it out yet. It could simply be a bad RAM stick or a configuration problem. It’s also a remote possibility that you have either a bad in-box speaker or that the driver for that speaker is corrupt. Heck, you might just have conflicts in general that just need a little tweaking. Until we can get you to the BIOS we really won’t know. If you have another RAM stick that you know is good, put that in as well. Make sure you put it in slot one.

Boot it up using a known good boot disk.

These basics will work for pretty much any 95x and newer systems. I’m assuming that since it’s an Athlon it’s fairly new.

I’m thinking that you have a bad power supply because your CPU fan works. That isn’t a given but from my experience that has been the norm. Sometimes the power supply will put out just enough power to light up the CPU fan but not the whole system. If you have a voltmeter you can test the output on the power supply. Depending on where you read it you should be getting either 5 volts or 12 volts DC. On the MB that should be regulated down to 3.3 volts, if I’m not mistaken.

It would help if we knew the system a bit better and what Operating System you’re using.

It might also help if one of the veterans on this forum offered a suggestion or two and/or corrected me if I’m mistaken because frankly I’m running out of ideas.

 

Thanks ShadowFax for the reply I will test your theory out.

There's just one thing that I'm not sure everyone is understanding. If you have the power supply connected to your motherboard and regarldless if you have the LED soft power switch hooked up to the MB or not, when the Hard Switch (Behind the machine) is turned on the MB should not turn on. This has been my experience with working on computers...if I am wrong and there are acceptions please correct me, because this idea is what is holding me back.

Shadowfax incase for some reason this MB is just 'different' I'll do what you suggest and I'll let you know.

Another quick note...once the MB is powered up by the hard switch, I can't shut off the machine with the soft power. I tried multiple switches by dismanteling a few other of my cases and still can't get the machine to turn off once the hard power is on.

Jaday97

 

BTW: There is no OS I'm starting fresh with a clean HD...the goal is to boot up off my floppy.

The machien is a AMD 600, and I'll look into the MB model once I get home tonight.

Again thanks for the suggestions.

 

I'm going to guess that when you swapped out the floppy drive, you may have created some static inside the case and blew something on the motherboard......

 

Hi jayday97

Just a few thoughts. Some bios hold the last condition (there is a setting on some) and will power up whenever power is supplied. Have you tried holding the front power button in for 10 seconds to see if the board will shut down? I suggest you put the memory back on the motherboard and disconnect the floppy drive when trying this.

 

Hi Lurker1

I'll put the memory back in....but the soft power switch doesn't shut of the power.

 

OK
It could be that the motherboard or processor is bad. But you also have a new case. Have you metered across the power on switch to be sure that it is OK? You could also short the two pins on the motherboard for the switch and see if that works.

 

how do I short the MB pins? and what would that accomplish or tell me.

 

The two pins that connect to the front panel switch could be shorted with a small screwdriver or a jumper plug. If this powers off the system then the front switch is bad or not being made when the front cover plastic button is pushed. This shoud be fairly easy to do if you have the motherboard outside the case as you said it is.