Power supply

[ssahl]

If I have a ATX 250 WATT power supply (Antec) that does not have a power switch on it and I plug it in, but the fan does not spin, doesnt that mean that the power supply is no good? I'm building a computer using an Intel 440LX motherboard that I have and I went ahead and bought a new Antec PC case with 250 WATT power supply and when I hooked it up I couldnt get anything. (no lights, fans, beeps, or anything. This is why I would think that the power supply is bad, even though I bought it new. If the motherboard was no good I would at least get the fan from the power supply to turn right? My main concearn is that before I hook up another power supply to it, could there be some kind of freak reason that my motherboard toasted the power supply? Aside from hooking it up wrong. The only things that were connected to the motherboard (aside from the power supply) is a video card, flopply drive, one memory strip, and a hard drive. Its not a big deal to take it back, I just dont want to make the same mistake again. (If infact I did make a mistake)

[morriswindgate]

Do you the case switches hooked to the motherboard correctly. With an ATX power supply, the signal to turn on the power supply comes from the motherboard and that signal is generated by the case's momentary power switch when it is pressed. You can also send this signal to the power supply by shorting across the two pins on the motherboard where the case switch plugs in. Be careful if you are planning to short across these pins, and do it only long enough to get the power supply to turn on.

[ssahl]

Yes I know I hooked it up right. The power switch is only two wires and I hooked it up next to the two pins that said power on with the lable facing the front of the PC just like it said. I'm wondering if it would be better to hook the power supply up to it from my computer or hook the power supply in question up to my computer. If the power supply was bad and I hooked it up to my computer (known to be good and working motherboard) it would not do anything to it would it? I know if I did one or the other it would tell me right away which was bad, the motherboard or the power supply, I just do not want to fry the power supply or motherboard from my good and working computer just to find out.

[morriswindgate]

If you have access to a known good ATX power supplu hook it up and try it. This will help narrow it down to bad power supply, bad case switch, or bad mobo. Also make darn sure you have the cpu, ram, and video card installed correctly.

[Cricket]

Hi ssahl,

Your motherboard may be shorting out against the case somewhere, this would prevent your system from powering up. Follow the instructions here: http://forum.pcmech.com/showthread.p...threadid=12753 before doing anything else.

Cricket

[Carl Price]

Also, some mobos come with the cmos clear jumper in the clear cmos position. This will cause exactly the conditions you describe. And as MorrisWindgate said make darn sure the ram, Cpu, and video card are inserted fully and correctly.

[ssahl]

Ok making progress, power supply works. I think that the socket 1 adaptor card (to PGA 370) was not compleatly all the way in the motherboard, either that or the motherboard was shorting out somewhere. I cant get any BIOS beeps though.
The power supply fan comes on, the power LED on the case comes on, the lock keys on the keyboard flash, and when there is a hard drive connected you can hear it start to spin and also the hard drive LED will flash. There is no "clear jumper setting" on the motherboard, there was a "normal, config, and recover" jumper settings that was set on config, which I changed to normal, but I dont see this changing anything. It has an AGP slot for the video card, would using an ISA video card cause a problem? My other computer has built in video so I didnt really have anything better, but I know it works. Since I dont hear any beeps I'm guessing that it is not doing any kind of POST test, and the monitor only says "no signal" that pretty much something wrong with the motherboard, this is my guess. Is there anything else that someone may know that I'm missing that I can check or try? I know that the actual CPU is good, and so is the memory strip, as for the slot 1 adaptor I dont know. If the reason for my problem is the bios bad, corrupted, missing or whatever, is that an easy fix? I wouldnt think that a bios upgrade and flash program on a floppy disk would work in its present condition would it? Any and all help is greatly appreciated.