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Faulty power button?

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19 replies

by kentontator

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I have a PC that will not turn on. The motherboard shows it is getting power (via LED light) but when I click the power button nothing happens, no fans start up, no posting or anything. I have replaced the PSU still nothing. I unplugged and removed all unnecessary components and still get nothing.

the only thing I can think of is a bad power button, is this plausible? Or does anyone have anything else I could try.

19 replies

by cmiller5400

but you should be able to confirm that by simulating the press by quickly connecting the two pins that the power plug connects to. BECAREFUL...

by ---tk---

take the power +/- connections and switch them with the reset +/- connections. Now your reset button is the power button, and your power button is your reset button... This is just a quick fix to test and see if its actually the physical button... Or you can leave it like that.. What ever works!

by ic-it

You may remove the proper jumper leads and briefly touch a conductive metal object to bridge the connection (as was indicated above this replicates the same action that the power button provides).
First though, you may want to id the leads and follow them to the front case cover to verify they haven't come loose.

by spc_tcol

You can use an Ohm meter and measure if the powerswitch works when you press it.

by ---tk---

as last resort you could alway remove the +/- connections to the button, take a flat head screw driver and touch the + then quickly touch the - at the same time... Which will simulate the button push...

Or if you have time, you could do a motherboar swap (I would do this first, before the hack job).

**Note - I have never done this, and I have only have only "heard" about it! It is very VERY risky... But if I had no other choice, I would try it knowing that I could fry the board...

by ic-it

There is little if any risk.
It is a nice quick way to rule out the power button.

by snuffy09

i assume something happened before the computer wouldnt start causing you to try and change the PSU.

Maybe the motherboard is toast?

make sure the ATX 20/24 and P4 power connections are both plugged in,
and double check pin configuration for power switch

do you have another case to install it in?
better yet if you had a junk case you could remove the power switch from.

by kentontator

My dad was the one who tried the power supply thinking it was that...he doesn't know much about computers but the problem has always been the same.

by snuffy09

if you changed the PSU & still get nothing then could very well be a bad motherboard.

are there any dark looking or burnt capacitors on the motherboard?

how old is the mobo? and what brand was the computer? if it was dell or HP they typically have pretty good warranties (3-5 years) and will ship you out a replacement part pretty quickly - you can do an online chat with them

by kentontator

I will try this when I get home tonight and report back with findings. Thanks for the idea.

by kentontator

All the capacitors from what I recall look alright, I will give them another glance when I get home from work. I believe the machine is a e-machine so I'm not to sure about the warranties on that.

by kentontator

I actually wanted to take the power switch out and test it with another, but unfortunately the only other two computers I had at my disposal were older motherboards and had different connectors. Gonna try a flat head when i get home.

by thechas

Based on the responses, it is very possible that there is a failure on the motherboard.

Often if the power supply does fail, it will damage the motherboard in ways that are not visible to the naked eye.

If the caps all look good with no bulging of any kind, the next thing to try is a full reset.

Reseat the CPU and RAM. Clear the CMOS. Then see if you can boot up.

If possible, try different RAM as that can also help.

Chas

by kentontator

Tried starting it with my flat head, no luck. Cleared the CMOS no luck, also tried both stick of ram 1 at a time, no luck. I am guessing the MOBO is trashed, thanks for the help and tips guys.

by snuffy09

i think im the only one that suggested a bad motherboard

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