ASUS u31sd LAPTOP WILL NOT TURN ON

[selldoor]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

On those readings where you say 1 is it 1 on the right or 1 on the left
(same as probes apart) meaning off scale/outof range.

[heavymachines]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

On those readings where you say 1 is it 1 on the right or 1 on the left
(same as probes apart) meaning off scale/outof range.

1 on left means pin 1....and on far right meaning what you said ...i think he understood...want to retest out of circuit....does not look right....meaning open circuit ....from what i am gatering even thou i cannot find exact data sheet on this ic but many forums claiming to have problems with this ic and i found where you can buy this ic but want to confirm with a retest out of circuit ...what do you think?

[selldoor]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

With you all the way - I worded my query badly I was only referring to
the results that appeared on his meter- we have had lots of cases where
1 meaning open (OL) has been mistaken for 1 meaning 1 or even O when the meter has been so far out of calibration or the battery going flat.

I cant find a data sheet either.

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

I can solder I'm a jeweler. I have repaired a few TV's I replaced a ic on a 42" phillips tv. But you have confused me on the number 1 pin location. in past postings you said there was a indentation for pin 1 how your saying when i remove ic to line it up with white line or arrow. I see a thicker white line on one corner of ic. So where do i aline it to ?

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

How do I go about testing the mosfet 8 pin when I get it out?

[heavymachines]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

I can solder I'm a jeweler. I have repaired a few TV's I replaced a ic on a 42" phillips tv. But you have confused me on the number 1 pin location. in past postings you said there was a indentation for pin 1 how your saying when i remove ic to line it up with white line or arrow. I see a thicker white line on one corner of ic. So where do i aline it to ?

that white line you see on motherboard indicates that pin #1 faces towards ..the indent on the ic is #1 pin so the indent on ic will face towards the white line....

[selldoor]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

This is the usual test - problem is we have no datasheet?
Some mosfets are more than 3 pins. To test those, identify the part number and search for its datasheet. Once you find the datasheet, the pins will be designated source (S), gate (G), and drain (D). It will probably be documented as S1, S2, G1, G2, D1, D2.

Simply test

a) black on pin S1- red on pin G1 - record ohms
b) black on pin S1- red on pin D1 - record ohms
c) black on pin G1- red on pin D1 - record ohms

Repeat for the "2" pins. That is S2-G2, S2-D2, G2-D2.

[heavymachines]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

How do I go about testing the mosfet 8 pin when I get it out?

same way, red probe on pin #1 set dmm to continuity and black probe on the pins one at a time on the other side of ic while keeping red probe on #1 and move black probe 1 pin at a time to get readings and move on down till you get all 4 on that side of ic which is the opposite side of where pin#1 is.. and post results make sure your dmm has good battery in it... set to "diode" for continuity...check to see if it still reads "open" or dead short if it does it will need to be replaced and may solve your problem provided there is not another bad ic in line in circuit...

[heavymachines]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

also found cheaper ic on ebay for 6 bucks...

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Here's a picture of the mosfet 8 pin. I have put a pink dot where the indentation is and a pink line where the white line is

[heavymachines]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

This is the usual test - problem is we have no datasheet?
Some mosfets are more than 3 pins. To test those, identify the part number and search for its datasheet. Once you find the datasheet, the pins will be designated source (S), gate (G), and drain (D). It will probably be documented as S1, S2, G1, G2, D1, D2.

Simply test

a) black on pin S1- red on pin G1 - record ohms
b) black on pin S1- red on pin D1 - record ohms
c) black on pin G1- red on pin D1 - record ohms

Repeat for the "2" pins. That is S2-G2, S2-D2, G2-D2.

that will work as well

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Guess it would help if i put the picture in here it is.

[heavymachines]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

this is how it should be....

[heavymachines]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Guess it would help if i put the picture in here it is.

that is incorrect....i can barely barely see it but the dot is indeed by the white line....

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

There's no indent on this one the numbers are the same,so are the markings.

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Using the white line as pin 1. I have my DMM set to 2000k when you check the pins the meter just keeps going it will not stop or hold on a number. number I'm reading just keep getting higher all pin are doing it

[heavymachines]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

Using the white line as pin 1. I have my DMM set to 2000k when you check the pins the meter just keeps going it will not stop or hold on a number. number I'm reading just keep getting higher all pin are doing it

try diode mode .. if it reads and is not open or shorted then it probably ok ...but can't confirm 100% due to lack of data sheet...but they got em on ebay fer like 6 bucks a piece .... or can buy 5 at a time... but try diode mode and if no open or short reading then will assume it ok and try to test the regulator....

[heavymachines]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

very faint but looks like a white dot this will mean pin one....

[heavymachines]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

opamp can you find data sheet on this board? i am having no luck...



please double check the motherboard part/model number to aid us in finding a darn schematic for this beast... gonna do some research on this and see if i can find anything and if the part/model number is wrong we will never find it....


need to see how this thing is set up if no luck still after hunting for schematic , i will have you do some live tests but let me research and study the pics of board so i can map out rough idea how this board is wired up...

if we find schematic that would eliminate alot of guess work....

[CR Designs]

Re: ASUS u31sd LAPTOP WILL NOT TURN ON

There's no white dot in what you have circled in picture the dot to the right of the pink line is solder or a pin from the other side of the board. My DMM doesn't have a diode mode. I have another DMM with auto range