power button

ricky246

New Member
Hi,

I have a problem with my Acer Aspire 7540G.
The power button didnt respone anymore. I took it apart and only with wires i could turn it on.
To connect the one end of wires togetter end the other ends each wire to the power button pins end i did boot normaly fine.
So i dicided to buy a switch and solder that to the motherboard.
first i tried it with my fingers and all was working the button was fine.
So i go soldering the button.
When i was done and gave it a test. it didnt work.
I took it off and tried with wires again.
The power cable LED didnt respone when i plug the power cable in.
And when i put wires the pin ends of the power button. the power lights did light up. But when i release the wires the laptop didnt boot.
So i hold the wires in place(same as holding the power button) The lights came on the fan spins...
for only 5 seconds and the stops end the screen wont come on.
nothing. as if it was dead.
But i only mass around with the power button.
Whats the problem now??????

Rick
 

_Kyle_

Well-Known Member
To be honest it might be something else shorting out causing the power button to be wonky. I would take in to a shop in this scenario.
 

ricky246

New Member
But before i solderded a external power button everything worked fine.
Maybe the powet suply?? I will try another power suply
 

ricky246

New Member
In the photo you can see on the left the button..
The scratches there where the wires i took off... maybe i damaged something??
Look at EC3 what are these for??
 

_Kyle_

Well-Known Member
In the photo you can see on the left the button..
The scratches there where the wires i took off... maybe i damaged something??
Look at EC3 what are these for??
It looks like solder for something on the opposite side of the board. Try re-soldering it?
 

ricky246

New Member
I will try.
But i think it is for the button.
I took off the button cuz maybe its damaged.
I will replace it for a fres new one.
But those two dots EC3 there goes a circuit line to undernee the button.
I cant find i diagram from this board. So i really dont what thease for.
But i will try to solder a new button and try another power suply.
But i thought maybe there is someone here on the forum who knows the problem.
 

Cromewell

Administrator
Staff member
It's easy to test the switch, use a multimeter and test for resistance, there should be infinite resistance unless the button is pressed in which case it should be 0.

I'm having trouble following what it looked like before you soldered the new button. Can you draw it out? Maybe it's just the bit where you added extra wires that's confusing me.

Did you replace the switch with the same type? There looks to be 4 poles on the one you put on. What about orientation, if that correct?
 
Last edited:

ricky246

New Member
The orginal button was broken.
To turn it on i had to connect to point manualy with wires.
So i know the button was broken cuz the laptop perfectly booted.
So the laptop was fine only i needed turn it on manualy with wires.
I bought a momentary switch.
I put wires to the new switch.
With my fingers i put no + c on the two contact points i push the button, and every thing was fine the laptop booted normaly.
So i grab my soldering iron and start soldering.
When i was done i tryed it again. But i didnt work.
I had to keep the button pushed. Only than de fan starts spinning but i cot black screen.
Also the lights for the power cable didnt work anymore.
Maybe i damaged the board with soldering.
I already tryed a nother power cable... dint do much.
To morrow i will start tesolder EC3 cuz it looks damaged and i goes under the button.
I dont know..
 

ricky246

New Member
Here is a photo. i already took off the broken button.

The red dots:
These two need to be bridge together end the laptop wil turn on. So i soldered the new to that points.

The purple dot:
Look at EC3 i dont know what its doing but i think its for the button cuz theres a circuit line from EC3 to under the button.
And maybe i damaged it. Maybe if i desolder EC3 And put new soldering points on it will fix it??

The green dots:
These are lights indicators that the power brick is pluged in.
Before soldering they worked. now...not anymore no power on the LED's

The black dot:
This is power brick input on the other side this is the botem.

I cant find a diagram of this mother board to see what EC3 is for but maybe it is damaged.
Other wise maybe its dead i dont know
 

Attachments

  • 20180816_164707 mmmmmmmmm.jpg
    20180816_164707 mmmmmmmmm.jpg
    766.7 KB · Views: 8

Cromewell

Administrator
Staff member
Maybe i damaged the board with soldering
It's possible. The heat from the iron can travel a fair distance from the solder point into an IC nearby. And the traces in the PCB can be quite small.

Or is there any solder that's shorting something that shouldn't be?

Does it still power on if you manually short the red dot points with the switch removed?
 

ricky246

New Member
Does it still power on if you manually short the red dot points with the switch removed?
When i plug the power brick in no powee LED's wil come on.
When i manually short the red dot points the power LED's come on. But i need to hold those two points connected. (It the same as holding the button down)
While im holding the laptop start booting...it looks like it.
The fan starts spining for 5 sec. And the harddrive spins. But nothing on the screen.(remeens black)
 

Cromewell

Administrator
Staff member
Integrated circuit. Any small chip nearby. Technically you can damage any component with too much heat when soldering though.

If EC3 is now shorting to something, I'd clean that first and see if it's better.
 

ricky246

New Member
Well clean EC3 and put a new button on it... its still doing the same..
Any sugestions what it could be...
im out of ideas.
Maybe its dead... but only because of soldering??
I did some multi meter. cant find anything
 

Cromewell

Administrator
Staff member
I don't know what it does. Looks like some kind of small IC from the other schematics I can find for SC1KP50V2KX-1GP. There looks to be a capacitor in front of it as well.
 
Top