ASUS u31sd LAPTOP WILL NOT TURN ON

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Since I have a picture of this up what is it,see post 214. It has a black body and 1 leg on one side and 2 legs on the other.

What is it?

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Ok Its a 1n4148 diode. It needs to be replaced here's a link

http://www.ebay.com/itm/QTY-15-1N414...item3cce4d3f07

Will order it

[opamp]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Start checking the mosfet these are numbered 7030AL look at the picture. Put your neg- probe on pin 8 and the pos+ on pin 1. They should have reading one way only.

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Start checking the mosfet these are numbered 7030AL look at the picture. Put your neg- probe on pin 8 and the pos+ on pin 1. They should have reading one way only.

I checked the mosfets 7030AL they read only one way.
The other 2 you had circled were not 7030AL, but 5030AL and they read both ways.

[opamp]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

I checked the mosfets 7030AL they read only one way.
The other 2 you had circled were not 7030AL, but 5030AL and they read both ways.

Those are bad too. Check all the them, I mean both sides of the board.

[opamp]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Here's the link for the mosfets. I couldn't find the 5030al but these should work they have the same ratings.

http://www.ebay.com/itm/2pcs-7030L-P...item19d06ce571

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Those are bad too. Check all the them, I mean both sides of the board.

I checked the MB front and back found 5 mosfets that didn't read right. To confirm how I read them is right see below i read across the 1 and 8 pin.

1... 8
2... 7
3... 6
4... 5

[opamp]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

This is how a mosfet works pins 1,2,3 are the same pins5,6,7,8 are the same. Pin 4 is the gate and supply's voltage to the mosfet so don't touch pin 4 unless you're checking for voltage. When you check the mosfets your DMM is on diode, right?

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

This is how a mosfet works pins 1,2,3 are the same pins5,6,7,8 are the same. Pin 4 is the gate and supply's voltage to the mosfet so don't touch pin 4 unless you're checking for voltage. When you check the mosfets your DMM is on diode, right?

so explain how to check mosfet. according what your saying in the above post. I can touch any pin on the1,2,3 side and any pin on the 5,6,7,8 side. so I can touch the 1 pin one side and on the other side touch the 8 pin. how would this be the same to test touch the 1 pin on one side and touch the 6 pin on the other side? Is this correct

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

This is how a mosfet works pins 1,2,3 are the same pins5,6,7,8 are the same. Pin 4 is the gate and supply's voltage to the mosfet so don't touch pin 4 unless you're checking for voltage. When you check the mosfets your DMM is on diode, right?

set to diode found 5 mosfets that did not read right

[opamp]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Yes pin1,2,3 are connected together and pins 5,6,7,8, are connected together only pin 4 is not because that's the gate . If the're voltage in pin 4 mosfet is on if no voltage the mosfet if off. Just image pins 1,2,3 are the pin on side of the diode and pins 5,6,7,8 are the pin on the otherside of the diode and 4 pin turns it on to allow voltage to pass.

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Yes pin1,2,3 are connected together and pins 5,6,7,8, are connected together only pin 4 is not because that's the gate . If the're voltage in pin 4 mosfet is on if no voltage the mosfet if off. Just image pins 1,2,3 are the pin on side of the diode and pins 5,6,7,8 are the pin on the otherside of the diode and 4 pin turns it on to allow voltage to pass.

O.K got it, how what's next

[opamp]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

O.K got it, how what's next

Make a list of what's bad so you can order it. What were the readings on the mosfet that you say are bad?

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Make a list of what's bad so you can order it. What were the readings on the mosfet that you say are bad?

O.K will make a list of bad mosfets and how they read. Also are you seeing any light at the end of the tunnel. Like what's wrong

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Make a list of what's bad so you can order it. What were the readings on the mosfet that you say are bad?

Bad mosfets
5030AL 007....007
5030AL 007....007
7030AL 562....533
5030AL 312....332

[opamp]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Without a schematic is very hard the only thing to do is to replace all bad parts that you find and hope it works.

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Bad mosfets
5030AL 007....007
5030AL 007....007
7030AL 562....533
5030AL 312....332

Were can I order these parts

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Are we done guys?

[selldoor]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Opamp posted an ebay link where you can buy?

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Parts are ordered