Had someone give me a non-working eMachine. Wouldn't power up.
Power supply doesn't come on.
Disconnected all cables except power connected to HD and CDROM.
Did the paper clip trick (I haven't received the tool kit yet...still waiting).
Power supply fan comes on, HD spins up and CDROM comes alive.
Okay, the power supply will at least do something.

Pull out paper clip. Connect to motherboard, yet I have everything else disconnected...no RAM, CPU, fans, HD...nothing else connected. Will not power up. I do the screwdriver trick on the pins on the MB just in case the power switch isn't working. Nothing. I hook up the power switch lead to the motherboard (which is the only thing connected to the mainboard.) Nothing works at all.
Add to all this....I find a little bit of black, powdery residue on top of a capacitor on the motherboard next to the ATX1 connection.
All this sounds like a bad motherboard.
Did I do this in a systematic way and is my conclusion logical?

The cpu is in the motherboard?

apart from the main 20 or 24pin atx connector is the a four pin atx (top pic), and is that connected?

maybe the power supply isn't powerful enough? thats very unlikely but just a suggestion.

I tried both ways....with the processor on the board, and with it removed.
It seems that if the power supply is connected to the motherboard...regardless of what or is not connected to the motherboard...it will not operate.
When I opened the case it was connected with the standard (long) ATX connector. I'll double check on the 4 pin connector. I don't recall it being connected or being used.
The power supply being too weak did occur to me, but it did seem to power the hard drive and the CDROM okay.
I'm waiting for my PC tool kit. Will the power supply tester help determine if it is too weak?

If the main 20 or 24pin atx lead and the 4pin atx (it would have to be a very old board not to have one) and bios battery in place, does the cpu fan spin up when you switch on or short the pins with a screwdriver (make sure its plugged into the header on the motherboard of course) .

I'll check when I get back to the shop. I don't recall the 4 pin just off hand. If it was hooked up, nothing came on..not the power supply...nothing. I thought I had a dead power supply until I tried the paper clip trick.

Okay, yes it does have the 4 pin. Tried both of them connected. Power supply does not power on. The short-trick between the 2 pins of the power switch port makes no difference.
I have tried every configuration I can think of.
Regardless of what is or is not installed or connected in or to the motherboard, if the power supply is connected to the motherboard at all the power supply will not come on. If the power supply is not connected to the motherboard (using the paper clip trick) and with the power leads connected to devices such as the HD and CDROM, the power supply will come on.
I have talked to the original owners. They said at first the modem went out, and then the CDROM would not eject at times. (I did remove the modem.)
Adding all this together, it sounds as though there was a surge that perhaps came through the phone line.
I'm still leaning toward a bad motherboard.

With both atx connected,
cpu installed,
heatsink installed and fan conneced,
bios battery installed,
shorting out the on/off switch pins, if it doesnt fire up and cpu fan spin, i would try another psu as last resort if that doesnt work bin the motherboard.

I just learned something interesting.
If you replace the motherboard of an eMachine and then try boot up, it won't work correctly. The OS in the machine is set up to work only with the motherboard provided by eMachines. The restore discs will not work with it either. If you replace the motherboard of the eMachine, you'll have to provide your own OEM OS.
I didn't know eMachines was that proprietary.

Originally Posted by busdriver72

I just learned something interesting.
If you replace the motherboard of an eMachine and then try boot up, it won't work correctly. The OS in the machine is set up to work only with the motherboard provided by eMachines. The restore discs will not work with it either. If you replace the motherboard of the eMachine, you'll have to provide your own OEM OS.
I didn't know eMachines was that proprietary.

Emachines dell and every other big name that supplies computers tattoos their board, which means buying a new one from them, its a scam and its the main reason they dont give you a microsoft windows install disc, you dont need a new os youve already got a perfectly good key all you need is an install disc and type in the activation key and it will work, its just useing a restore partition or disc thats no good, can you get hold of a install disc.

and anyone who is planning on ever buying a computer INSIST on an installation disc, if they try and fob you off with a restore disc or partition tell them to shove their computer where the sun doesnt shine (preferably sideways) if you put up with companys ripping you off dont start bitchin about it, ask for a genuine windows installation disc, if the answers no walk away.