Anyone good with electronics?

[Bandeen]

Hey all,

Ive taken my old laptop apart as the screen doesnt work and I have other plans for it, I need to remove the old push switch to turn the unit on and replace it with my own. I have removed the chip with the mini switch on it, can anyone tell me which parts I need to solder new wires to allow for my own switch?

I know that I basically need 2 positives or to add the wire in the positive line, im just not sure which ones they are.

Here is the board:

http://www.bandeen.co.uk/misc/chip1.JPG
http://www.bandeen.co.uk/misc/chip2.JPG

Any help appreciated, Cheers!

[f12f12]

that is a very tricky one there, its got me confused. is there a possibility its a 3 layer pcb?

it looks like power runs in on one side of the board and out the other? and passes through a resistor and then the switch.

judging by the resistors + i would say negative is running on the bottom side of the board. but i can't see where it runs after the resistor to the switch?

another thing are you sure its standered and not digital?

[Bandeen]

another thing are you sure its standered and not digital?

Nope lol! Im also puzzled by the board too, the only thing I thought about doing was removing the switching and having a look to see if theres any more info there.

[system7]

You would think that top left switch is just a momentary contact when pressed between the two incoming traces going to an IC, with an earthed shield on the PCB. The LED below is probably lit by two wires from the IC elsewhere.

I'd check it with a resistance setting on a multimeter. But I expect you could piggyback a standard PC power button like on the front panel of a PC.

[f12f12]

i guess to be totally sure you would need the making instructions or to test it with volt and amp meter and on a scope.

[f12f12]

You would think that top left switch is just a momentary contact when pressed between the two incoming traces going to an IC, with an earthed shield on the PCB. The LED below is probably lit by two wires from the IC elsewhere.
.

its a LED????

[system7]

its a LED????

Well, that was a guess...LOL

I expect Bandeen knows. LD7 suggests diode at least. :confused:

[Bandeen]

Hey yea its an LED under the switch! It turns on when the laptops on to indicate the power is on!

Well ive taken the switch off, will update with a picture in a wee whiley :D

[Bandeen]

Ok here is the updated pic of the mini switch removed! I just need to find out where to solder a new push switch onto it and we are rolling lol!

http://www.bandeen.co.uk/misc/chip3.JPG

[system7]

If the switch is separate from the LED, I'd guess NW to SE in points of the compass for momentary contact. This is where testing the switch with an multimeter would help.:xsmile:

Just did an edit...LOL..forgotten how a compass works.

[Bandeen]

How would I do this with a multimeter when not plugged in, would I use the continuity(sp!) test to find which to make a noise when bridged?

Cheers for the help so far!

[Bandeen]

EDIT: OK just done the test, I have added a new pic with my findings, the multi meter makes a "buzz" in continuity mode if the pairs are match up as below (pairs are indicated with a red and orange line). If I touch a spot from opposite corners it doesnt work.

So could I just pick a pair to use and try that? Or do I need to use both pairs? Like both poitns from one side going to one wire?

http://www.bandeen.co.uk/misc/chip4.JPG

[Bandeen]

WOOP WOOP!! :D :D :D

Found it! If you touch a bit of metal between the either side as marked on my new diagram in pink, the unit will power on, hold it again to turn it off (or shut down via windows!)

http://www.bandeen.co.uk/misc/chip5.JPG

This will now allow me to get on with a compact car PC :D Just have to remove the old power switch cover, put new wires on to allow a push switch from up front in the dash.

Cheers all for the help, will keep posted with progress... now just have to put it all back together!! :D

[system7]

Yup, I can see that now. The top two pins need a momentary short to the bottom two pins. :thumbs: