At Fixya.com, our trusted experts are meticulously vetted and possess extensive experience in their respective fields. Backed by a community of knowledgeable professionals, our platform ensures that the solutions provided are thoroughly researched and validated.
Plugging in the power supply, the mobo LED light inside becomes lit. I hit the power button and the power LED light becomes lit but nothing else kicks in (fans, HDs, bios, etc.). There's a "Test Switch" on the power supply so I pressed it and held it in and the computer boots up normally as long as I keep my finger on the switch. If I were to let go, everything but the power LED light and the mobo LED light goes off. Say I hit the power button for 5 seconds to shut it off. Now when I hit the "Test Switch", the CPU fan and the power supply fan turn on but, of course, the HD and everything else won't because the power button wasn't hit. There are 5 wires coming from the power button area. Three wires are coming from to the dual-color power LED (green/red for standy mode). The other two come from the power button switch. The opposite end of the wires go to the motherboard grouped together.
It seems that the power supply is operating fine when I hit the test switch on its side. This must mean that the mobo isn't signaling the power supply to power up when the power button is hit. I can't imagine the power button being bad because the LED does light up when the button is depressed. Does anyone have any ideas what could be wrong?
thanks for the suggestion. i know the switch is fully functional; i've tested it independently. as an experiment, i've also took the PS_ON signal from the power supply and connected it to ground and watched it power up just fine. (i've also tested the power supply by using it in another computer) The only way I could get it this PC to fully work is by hooking up a transistor to connect the PS_ON signal (to the collector/drain), ground (to the emitter/source), and the wire going to the power on LED in front of the case (to the base/gate). That way, when the power button is pushed, the motherboard sends the signal to light up the front LED (which it originally did) and, at the same time, send a signal to the transistor to bring the PS_ON signal to ground. When the PS_ON signal is grounded, the power supply activates all of its power lines going to the components like the hard drive and stuff and the computer boots up fine (which is what i experimented with earlier).thanks for the suggestion. i know the switch is fully functional; i've tested it independently. as an experiment, i've also took the PS_ON signal from the power supply and connected it to ground and watched it power up just fine. (i've also tested the power supply by using it in another computer) The only way I could get it this PC to fully work is by hooking up a transistor to connect the PS_ON signal (to the collector/drain), ground (to the emitter/source), and the wire going to the power on LED in front of the case (to the base/gate). That way, when the power button is pushed, the motherboard sends the signal to light up the front LED (which it originally did) and, at the same time, send a signal to the transistor to bring the PS_ON signal to ground. When the PS_ON signal is grounded, the power supply activates all of its power lines going to the components like the hard drive and stuff and the computer boots up fine (which is what i experimented with earlier).
i agree...it is the motherboard..the only way i was able to reuse the motherboard was to buy a PNP transistor and wire stuff up from the power supply to the motherboard...crazy and not recommendedi agree...it is the motherboard..the only way i was able to reuse the motherboard was to buy a PNP transistor and wire stuff up from the power supply to the motherboard...crazy and not recommended
AnonymousDec 10, 2008
yes i have the same problem. This hhappened when i switvhed cases from the stock to a cooler master case. I plugged everything in correctly and the screws on the motherboard arent too tight. When i start the computer teh fans go off for a split second and dies. I know that my mother board works b/c when i switch cases back to the stock case it boots. Plz helpyes i have the same problem. This hhappened when i switvhed cases from the stock to a cooler master case. I plugged everything in correctly and the screws on the motherboard arent too tight. When i start the computer teh fans go off for a split second and dies. I know that my mother board works b/c when i switch cases back to the stock case it boots. Plz help
AnonymousJan 16, 2009
I have a similar problem with my Gateway. I really do not know that much about computers. If this fixable, or should I just get a new motherboard?I have a similar problem with my Gateway. I really do not know that much about computers. If this fixable, or should I just get a new motherboard?
AnonymousMay 22, 2009
INSIDE motherboard led works power up don't work
INSIDE motherboard led works power up don't work
You can't post conmments that contain an email address.
That's what I thought too. Because I also swapped my power supplies with my other comptert and that did nothing. So I order another MB and cpu, and guess what? The same problem! I'm at a loss especially since this should be an easy fix.That's what I thought too. Because I also swapped my power supplies with my other comptert and that did nothing. So I order another MB and cpu, and guess what? The same problem! I'm at a loss especially since this should be an easy fix.
You can't post conmments that contain an email address.
I'm wondering if you have the jumpers set for the power button correctly on the motherboard. If the test switch is working properly when held in, then there's something wrong with the power button itself (maybe it's not going in enough to turn it on? I've had that problem before and had to McGuyver it with super glue and a little wad of paper to work correctly)
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Have you checked the keyboards light? Is it lit? When you press on the CAPSLOCK button, does the light changes in the keyboard?
Try to unplug the hard drive, and DVD from the mobo and see if it goes well.
If no go, try removing the RAM sticks and see what's on the screen when you turn it on. Then put each part back one by one, checking the computer for any change or something like that.
Power supply has several voltages. Just because the 5v power is active doesn't mean all the voltages are OK. You need to have the power supply tested for 12v and 3.3v. A quick test is to unplug all the wires from the power supply. There is a single green wire on the motherboard main plug. Connect (use a bent paper clip) that green switch wire and any black wire. Plug in the power supply and it should run (fan starts)
It seems like you have bad MOBO. I recently ordered all the stuff to build 2 new systems. Built the first one, no power, just like yours. Moved everything to the 2nd MOBO, everything worked. I did a RMA on the DOA MOBO. Got the new one and it fired right up. Sometimes you just get bad stuff.
Either the board was damaged during the repair attempt, or was bad to begin with. The original problem description (black screen) sounds like typical mobo "no boot" trouble. The loose heatsink on the chip may have contributed to the failure, or it may have been simply coincidence. Given the low cost of motherboards, it's silly to spend any more time on attempting to diagnose and repair a problem. Just replace the board and move on.
Power supply is easier to troubleshoot my local pc shop has used ones for $5 or if you have one laying around make sure you have one with the proper mobo connector 24pin will sometimes fit 20 pin as long as there are no transistors to close to plug just turn pc off unplug all drives and mobo plug in good supply and turn on if it works thats the problem if not probably mobo
KingPin, is there any sign of life at all? Any lights, whiring, harddisk spinning?? Is there an LED (small light) visible on the motherboard when the power is on???
If nothing, certainly a power problem - but where. While you have the case open looking for the lit LED on the mobo, can you see any capacitors, the little cylinder-type components on the mobo circuit board that look like little batteries standing up, there'll be about half a dozen of them, that look like they may be bloated, or like a coke can left in the freezer about to explode. Do any of these capacitors look like they could be oozing goo, maybe a yellowish rusting liquid. If any do, this is not good.
If none of that applies the next step is to check your power supply. I would not suggest an amateur to do this over a step-by-step chat as it involves shorting out points and if the system is live, the wrong points shorted, well, guess you'd know what could happen (not good). The power supply is not easy to diagnos for errors, they're tricky buggers that can test well for voltage but once a load is put on them they roll over and play dead. Get an expert to test your power supply, very simple task of they plugging in a PSU tester (or borrow one, or buy one).
Please keep us informed on how you go - seriously, we grow stronger as we grow wiser when we finish a job.
**.The best way to acknowledge contribution is to rate it's relevance.**
Try a new power button. Also does the machine power light turn on at the front of the machine? if so check that the CPU is seated correctly as if it has come out of position then the machine doesn't boot. I would like to think power switch though.
it could be your power switch, veriy that it isnt the power supply by
1.) un-plug it from the main board
2.) look at the main board connector(one coming of the power supply)
3.) you should see green wire and next to it a black one
4.) using a paper clip bridge the too wires
5.) if it works proceed to net step if not get a new power supply
to check case switch and board switch
1.) plug in power supply to main board
2.) look at the pins where the power button connects to
3.) using a metal object (blade screw driver) bridge the pins
if the board should start up>
then its your power button on the case that is bad, you can try to repair it, chage it or buy a new case,
if it doesnt work.
1.) ensure that jcms(jumper to flash the bios) is set correctly
2.) unjack each drive one at a time to see if any is causing stalling
3.) get a new main board
ever happen to anyone?
thanks for the suggestion. i know the switch is fully functional; i've tested it independently. as an experiment, i've also took the PS_ON signal from the power supply and connected it to ground and watched it power up just fine. (i've also tested the power supply by using it in another computer) The only way I could get it this PC to fully work is by hooking up a transistor to connect the PS_ON signal (to the collector/drain), ground (to the emitter/source), and the wire going to the power on LED in front of the case (to the base/gate). That way, when the power button is pushed, the motherboard sends the signal to light up the front LED (which it originally did) and, at the same time, send a signal to the transistor to bring the PS_ON signal to ground. When the PS_ON signal is grounded, the power supply activates all of its power lines going to the components like the hard drive and stuff and the computer boots up fine (which is what i experimented with earlier).
i agree...it is the motherboard..the only way i was able to reuse the motherboard was to buy a PNP transistor and wire stuff up from the power supply to the motherboard...crazy and not recommended
yes i have the same problem. This hhappened when i switvhed cases from the stock to a cooler master case. I plugged everything in correctly and the screws on the motherboard arent too tight. When i start the computer teh fans go off for a split second and dies. I know that my mother board works b/c when i switch cases back to the stock case it boots. Plz help
I have a similar problem with my Gateway. I really do not know that much about computers. If this fixable, or should I just get a new motherboard?
INSIDE motherboard led works power up don't work
×