Asus x71v no power.

Board M70V rev 2.2

Hello,
I got this laptop which is in almost perfect condition but not powering. Battery missing.
Upon attaching the pwr adapter the pwr and start led blinks for fraction of a second. Power is on board but missing 3 and 5 volts. is the ISL6227 the source of 3 & 5 v? Getting 18.5 v at pin 14, VCC 0v, adjacent coil 0v. Getting tension on VCC and coil when attaching the adapter but upp to 4 v respectively 1v.

Board images, uploading some of them cause no component markings onboard which will make it difficult for me to identify potential suggested item!!

Any suggestions would be appreciated.

ISL6227 should control another voltages, not the system ones (3V/5V)...
Check M50 schematic, as example.
Look for TPS51020/51120, RT8206 or MAX17020 on your board; could be another chip, but you will find it surelly.
Find a similar schematic, using same chips. Is good to have one with same KBC.
Check FORCE_OFF# and EC_RST# (KBC reset).
M50/52/60 schematics should help you...
Check for short on secondary power supplies.

Hello,
Thanks for reply.
I found the TPS51020, the chip get a bit warm and the pin voltages are 0v except for the pins below
pin4= 1.1v
pin6= 18.75v
pin9= 2.5v
pin10= 2.5v
pin16= 4.5v
pin22=5v
pin23=0.5v
pin24=18.75v
pin30= 4.5v

As of the mosfets adjacent the voltages according to the pic

2informaticos napisał(a):Check for short on secondary power supplies.

Can you point out which

Look for a small 5 pins IC in that area...
Should be a regulator, to provide 3.3V from VREG5 (of TPS51020) to KBC.
If short found on its exit, probably bad KBC.

2informaticos napisał(a):Look for a small 5 pins IC in that area...
Should be a regulator, to provide 3.3V from VREG5 (of TPS51020) to KBC.
If short found on its exit, probably bad KBC.

I found three of these ICs at the are as the picture. With continuity measurement as of the picture the only pin reading 0 to ground are indicated in picture.

Any other way to measure the short of IC itself onboard would be appreciated.
Would you mind indicating the KBC on this board?

The one I have reffered, must have a common pin (input) with VREG5...
Look at this post
schemat-asus-x71sl-x71sr-t19635.html?hilit=x71sr
hope will help you.

2informaticos napisał(a):The one I have reffered, must have a common pin (input) with VREG5...
Look at this post
schemat-asus-x71sl-x71sr-t19635.html?hilit=x71sr
hope will help you.

99 % its this on


How to test short on it?

Do you have short, or low value to GND on JP8101?
If not, measure the voltage there...

2informaticos napisał(a):Do you have short, or low value to GND on JP8101?
If not, measure the voltage there...

I get 87ohms to GND at JP8101. Voltage here is 2.3v.
The above measurements are after changing the IT8512 and replacing the PS51020 with a whole new one.

The matter now is that when connecting the pwr adapter the short blink of start LED disappeared. But the PS51020 get hot in short time that I'm afraid it'll get bad. No boot yet.

Use M50Vm schematic, I think is close to your own.
U8102 is there the chip which generates +3VAO for KBC.
Post again values for TPS51020 pins, 24, 22, 8, 9, 10.
Also voltage and resistance to GND on pin5 of U8102. This chip goes hot too?
Open JP8101 and check again.

N.B. Please don't quote entirely my messages...
I don't see any reason to repeat same message which appears few cm above.

Sorry for delay, tried to test but the tps51020 burned. had to wait for new chips to arrive.
Ordered a new IT8512 cos the one i changed before was a usd one, just in case.

after soldering still heating the TPS chip. opened JP8101 and the chip not heating any more. These result with JP8101 opened.
TPS51020
pin 24= 18.5
pin 22= 5v
8, 9, 10= 0v.

GND-->pin5 of U8102= around 600 ohms
U8102 dont get hot.
pin5 of U8102= 3.3v

As i mentioned above the above measurments made with JP8101 opened.

GND-->pin5 of U8102= around 600 ohms
U8102 dont get hot.
pin5 of U8102= 3.3v

Did you check there closing JP8101 without KBC soldered?

Check now resistance to GND in the other pad of JP8101 (opened), which goes to KBC.
One component connected to +3VAO is still bad...

Did you check there closing JP8101 without KBC soldered?

Actually no.

Resistance to GND in the other pad of JP8101 (opened)= 470 ohms


Shall i allpy 3v 1amp to the kbc side pad of jp8101 and seek for heating components? bad for KBC?

Any support?

If TPS51020 only heats if you close JP8101, that means you have a problem on +3VAO line.
In case like this, bad KBC normally, but try removing all the components connected there.
Start with BIOS chip...
Only check the smallest voltage capacitors, not all of them.

Well as of the elements have no makring on board it will be difficult to trace the 3VOA/3VA line.
Any god tips how to determine how to know which. The bios chip is easy to point but the capacitors you are refering to ( which do you mean? ).
Do you mean those at IT8512 (power in) line according to M50vm schematics?
If yes, can i trace those to the capacitors attached to power in pins? there are capacitors connected to all power in pin except for pin 3.

As you mentioned the normal case is that the kbc is to blame, may be a defective chip i bought? i will try to order new but it shall take same time.

Can i apply 3 v CRC to the other pad JP8101 and what to expect?

Thanks for any input.
BR

Not too many components connected to +3VAO line; KBC, BIOS chip, lid switch and few capacitors.
These capacitors are 6.3V or bigger, so I'm pretty sure all are good.
Check them for corrosion only.
Remove lid switch, BIOS chip and KBC; start in this order.
Check the schematics as M50Vm, or other similar...
See if appears any other small chip connected there.
You can try injecting 2-3V there, but I'm not sure about the result.
The resistance with GND is not too low, so maybe nothing goes hot.
TPS51020 goes hot because its 5V LDO output support less than 100mA!

Was very hard to trace capacitor given the fact no marking on board and i followed the M50vm schematic as of the M70vn schematic not available. Nothing wrong with the capacitor.
Cant find the lid switch on board ( really tried ).
Lifted bios chip, TPS51020 still heat up directly after connecting adapter.
Lifted KBC without in addition to bioschip, the same heating of KBC.

On the other side of board found the CE8105 according to M50vn schematic shortened with 0 ohm on that line, changed and getting up to 27 ohms now. Opened the JP8104 and reading according to attached pic, the +5VSUS pad is reading 27 ohms. Even with jp8104 open the tps51020 heats the same.

Any more ideas, to look some where else are really appreciated.

[url=https://www.elvikom.pl/obrazki/_f/f_0023865.png][/url]

Check if lid switch (Hall sensor) is on the power button board.
If not, must be on the mainboard, close to one edge...
Take a screwdriver and move it close to the edge of lid and find where the magnet is. Then you know where should be the sensor on the board.
However 27 ohms on the +5VSUS line is not good at all; that suppose more problems, dificult to solve without schematic and boardview...
Leave that pad opened, until you get correct voltages for KBC at least.

Well the lid switch is not on board, its actually on the screen part so its not conneted by definition. Knowing that the tantalum cap was shortened i went through all of these capacitors on board.
I think all the Vcore 330uf capacitors are shortened, reading only 3 ohms to GND.
There is also one with 150 uf in vincity of 1.5v which is reading low about 17 ohms.

[url=https://www.elvikom.pl/obrazki/_f/f_0023871.png][/url]

The problem might seem bigger than it seemed from the begining. Do you think its worth to try a fix?