Help! Computer won't turn on!

[Kenshinn]

I've had this sony vgc-rb40 for 2 years. Its been working great and I added an ATI x800 when i first got it as well adding a gig of memory to it.

I moved this computer to my mother's room and it stopped working when it was working minutes before. This is what I noted. There is a green flasing light on the power unit and upon closer examination, there is a smller green flashing light on the motherboard right next to where the psu connects to it. Did I short something out?

I've tried unplugging the PSU from the motherboard and the light successfully stays on without blinking. I've also tried resetting bios through CMOS and battery. Any other suggestions?

 

[jjzelinski]

Never hurts to rule out the stupid stuff first. Try to make sure you're not overloading the AC circuit you have the PC plugged into. If you have a crappy electrical box it might not trip the breaker the whole way during overload and will only partially disengage. So make sure the breaker is good, make sure you not overloading the "outlet".

This might sound stupid but make sure you didn't switch the voltage on your PS. Many PS' have a switch that will allow you to manually alter the input voltage to allow for 110 or 220VAC. If you have it on 220VAC plugged into a 110VAC outlet there's your problem. The good news is that screwing up in the way doesn't hurt anything. Screw it up the other way and you'll be needing a new PS

If this ISN'T the case, start the barebones game and disconnect everything but the motherboard input power connections (20 or 24pin atx and 4 pin 12VDC plug near the CPU) and the necessary panel switches to turn your crap on. Now based on another threat I was just in, for the love of god don't mix up your 4 pin plugs as there might be 2 of them. One goes with a 20pin ATX plug, the other near the CPU. Now in most cases they're molded differently so you *shouldn't* be able to screw it up, but it happens so be careful. You might find yourself in a sorry boat having fried your mobo, PS, and god knows what else.

Now if you still can't boot you're going to have to get some substitute parts to start troubleshooting with. PS and Mobo would be a good start. CPU would be a distant 3rd.

 

[Kenshinn]

I just tried doing the process of elimination by unhooking the dvd drive, hard drive, etc. yet, nothing seems to work. I still get the flashing green. Also, i tried removing the memory as well as the video card.

 

[jjzelinski]

Sorry man but the times that I've seen the symptom you speak if it was because the 110/220VAC switch was in the wrong position. Now if your PS is autoswitching (which would be evidenced by both the lack of a switch and a message on the PS stating it's autoswitching) then it's entirely possible your PS croaked.

 

[hurtstotalktoyou]

Hmm. That's a toughie. So it was working, then you powered down, picked it up and carried it into another room, plugged it back in again and suddenly it wouldn't work. And you did not open the case in between, right? Well, let's see... I wonder if maybe one of your expansion cards has come loose when you were plugging everything in/out. I'd particularly check the video card. Other than that, I have no idea. Check to make sure the USB headers are connected properly (or disconnected). That can cause a power refusal.

 

[jjzelinski]

Originally posted by: hurtstotalktoyou
Hmm. That's a toughie. So it was working, then you powered down, picked it up and carried it into another room, plugged it back in again and suddenly it wouldn't work. And you did not open the case in between, right? Well, let's see... I wonder if maybe one of your expansion cards has come loose when you were plugging everything in/out. I'd particularly check the video card. Other than that, I have no idea. Check to make sure the USB headers are connected properly (or disconnected). That can cause a power refusal.

Oooh good call, I have seen loose cards do this before. Forgot about that

 

[Kenshinn]

Problem Fixed! Bought a 40$ 350Watt PSU and it worked. That was crappy timing. Question: How does a PSU burn out?

 

[hurtstotalktoyou]

Originally posted by: jjzelinski

Originally posted by: hurtstotalktoyou
Hmm. That's a toughie. So it was working, then you powered down, picked it up and carried it into another room, plugged it back in again and suddenly it wouldn't work. And you did not open the case in between, right? Well, let's see... I wonder if maybe one of your expansion cards has come loose when you were plugging everything in/out. I'd particularly check the video card. Other than that, I have no idea. Check to make sure the USB headers are connected properly (or disconnected). That can cause a power refusal.

Oooh good call, I have seen loose cards do this before. Forgot about that

Usually not a problem except with crappy cases. And of course I had the boneheaded idea a year or two ago of buying an LCT USB-07-4HL, so I have plenty of experience with it.

 

[jjzelinski]

Originally posted by: Kenshinn
Problem Fixed! Bought a 40$ 350Watt PSU and it worked. That was crappy timing. Question: How does a PSU burn out?

Nine time out of ten capacitors fail. That's what that lovely "burnt electronics" smell is when crap gets fried; it's the smell of burnt dielectric material that supposed to isolate the two electrical plates of a cap.

FOr slightly more info, power supply consist of two main parts; rectifier (converts AC to DC using a diode bridge) and regulator (made of caps, used to smooth out pulse to pulse variations to ensure the output power is consistent.) Normally its the regulator part that dies.