Asus Rog Laptop new battery still 0% Biard issue?

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

Although it is a typical way how a DC-IN Mosfet shorts out, your resistance measurements does not makes sense at all regarding the previous observation.

The two Mosfets on the first picture. What resistance do you measure between Source and Gate?

The Dual-Mosfet near the burned via might be a secondary(!) issue which you might want to rule out later.

i assumed that larger mosfet near the charger port was shorted but i learned thats not the correct way to measure by continuity mode. So i measured in diode mode to source and gate and its 0.9v . And on Drain its 0.4v on the left one and 0.9v on the right mosfet. So for the right mosfet its 0.9v all around basically is that normal?

[Sephir0th]

Re: Asus Rog Laptop new battery still 0% Biard issue?

Ohms mode is better to compare. How much Ohms are this 0.4v and 0.9v in diode mode?

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

Ohms mode is better to compare. How much Ohms are this 0.4v and 0.9v in diode mode?

ok in ohms i found many mosfets with low readings under 100 ohms. i heard they are supposed to be in the thousands or millions right? i did red probe on ground and blavck on spurce ( pin 1 ) where the dot is. But under 100 ohms is bad right?

[Sephir0th]

Re: Asus Rog Laptop new battery still 0% Biard issue?

Well, we're still at the two DC-IN Mosfets close to the charging port. I want to exclude one of them is (still) internal shorted and causing this behaviour. Forget all the other Mosfets present on the board for the moment.

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

Well, we're still at the two DC-IN Mosfets close to the charging port. I want to exclude one of them is (still) internal shorted and causing this behaviour. Forget all the other Mosfets present on the board for the moment.

source to drain is 1 ohm on the closet mosfet to the dc jack.. Bad ? Also had a small mosfet was measuring very low to and removed it and now that area measures in the kohms and the others near it are now measuring high to.. possibl lot of mosfets blew same time, what to do next ?

[Sephir0th]

Re: Asus Rog Laptop new battery still 0% Biard issue?

We are probably dealing with a language barrier or similar right now, since you managed to remove the wrong mosfet (picture 1) which is not part of our troubleshooting.

Please place it back immediately before doing anything else and ignore low values as long as they're not related to the DC-IN circuit. Just ignore each mosfet which hasn't anything to do with the DC-IN circuit please, like I told before.

And in future do not touch any component without advise please

Now to the second picture: Yes, 1 Ohms is a internal short and has to be solved. This one could be the culprit of your actual issue.

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

We are probably dealing with a language barrier or similar right now, since you managed to remove the wrong mosfet (picture 1) which is not part of our troubleshooting.

Please place it back immediately before doing anything else and ignore low values as long as they're not related to the DC-IN circuit. Just ignore each mosfet which hasn't anything to do with the DC-IN circuit please, like I told before.

And in future do not touch any component without advise please

Now to the second picture: Yes, 1 Ohms is a internal short and has to be solved. This one could be the culprit of your actual issue.

sorry just got impatient.. i put back the little mosfet but the 3 pin source always bridge even after cleaning the pads.. is that ok ? Also i removed that main mosfet near the dj jack and tested it out of the board and its shorted between source and drain.

[Sephir0th]

Re: Asus Rog Laptop new battery still 0% Biard issue?

All three pins of source are together anyway, so yes, no issue.

Wonderful, replace the mosfetwith a suitable replacement please and the issue should be gone.

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

All three pins of source are together anyway, so yes, no issue.

Wonderful, replace the mosfetwith a suitable replacement please and the issue should be gone.

so source and drain of the larger mosfet was 1 ohm outside the board thats bad correct? Also can i use similar looking mosfet off another asus laptop board i have? Or where can i buy one of these mosfets? i looked on ebay couldnt find any . The original is a NIKOS PKCH288 GUD201701

The one i want to use is a SM4309 RW6BY look similar and from same location near dc jack.
Thanks.

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

I found the mosfet thats on the same line of the battery positive line.. The drain of that bottom mosfet and the 3 pos batt terminal pins beeps that has to be the main batt mosfet right? I measured that mosfet source ohms and its 1 ohm( red probe ground and black to source ) . So im assuming the batt mosfet is bad? there are 2 other mosfets right above and the source on those are in the Mega ohms.. Also those two mosfets sourc's e has contuity with the batt terminal as well. But i think those 2 are good and the fist one is bad ?

[Sephir0th]

Re: Asus Rog Laptop new battery still 0% Biard issue?

SM4309 is a P-Channel mosfet and the old one is N-Channel so ofc not a suitable replacement.
Easiest and best advice is to replace with the exact male/model. Otherwise you have to pay attention to a few key specs, like Ids same or higher, Rds same or lower, Ugs breakdown same or higher, Ugs threshold same or lower, and so on.

This is no easy stuff and if we even have issues to differentiate P-Channel from N-Channel then i have doubts now

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

so i took out the sm4309 from the donor board and measured its around 5 megaohms drain to source.. just like the other original nikos one still on the board.. measures the same around 5 mega ohms. but the Suspected bad one measures nothing zero trued even flipping probes.. So that mosfet is bad for sure right?

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

I appreciate you helping me and having patients with me. As i dont have any patients ����

Where can i find NIKOS PKCH288 GUD201701 in the US? seems like all from china ?

[Sephir0th]

Re: Asus Rog Laptop new battery still 0% Biard issue?

A Mosfet which reads out of circuit below KiloOhms in any internal direction has pretty sure failed. This is why we measure it this way.
Can't help for sourcing though. Check local eBay and verified suppliers. Maybe it helps when you type the right model:

PKCH2BB instead of PKCH288

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

so can i test mosfet while on board? and whats the proper way to test ? oops ywah your right its BB not 88 lol.. You think that main mosfet is tge cause of the battery charging issue? i thought it would be something in the battery circuit. Also i noticed a lor of coils and diodes and mosfets source) have contuity with ground?? Is that normal ? like 1-5 ohms , wouldnt that indicate a short? but how can a laptop still work with that many shorts?

[Sephir0th]

Re: Asus Rog Laptop new battery still 0% Biard issue?

How many proofs do you need till you do what someone with experience advised?

It is widely known that a internal shorted DC-IN Mosfet can cause no charging. Oversimplified the adapter voltage will be just jumpered into the main power rail, although the charging circuit is not ready.

And regarding the "shorts", you have to differentiate between a Mosfet, which acts like a simple switch and mosfets which are part of a buck converter. If they're part of a part of a buck converter there is always at least one mosfet connected to GND. Otherwise the step down wouldn't be possible at all. you should read about some basics in this direction. They're absolutely necessary to not make the issue worse by random attempts.

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

How many proofs do you need till you do what someone with experience advised?

It is widely known that a internal shorted DC-IN Mosfet can cause no charging. Oversimplified the adapter voltage will be just jumpered into the main power rail, although the charging circuit is not ready.

And regarding the "shorts", you have to differentiate between a Mosfet, which acts like a simple switch and mosfets which are part of a buck converter. If they're part of a part of a buck converter there is always at least one mosfet connected to GND. Otherwise the step down wouldn't be possible at all. you should read about some basics in this direction. They're absolutely necessary to not make the issue worse by random attempts.

Thank you very much, i will order a couple PKCH2BB and hopefully that works!!

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

How many proofs do you need till you do what someone with experience advised?

It is widely known that a internal shorted DC-IN Mosfet can cause no charging. Oversimplified the adapter voltage will be just jumpered into the main power rail, although the charging circuit is not ready.

And regarding the "shorts", you have to differentiate between a Mosfet, which acts like a simple switch and mosfets which are part of a buck converter. If they're part of a part of a buck converter there is always at least one mosfet connected to GND. Otherwise the step down wouldn't be possible at all. you should read about some basics in this direction. They're absolutely necessary to not make the issue worse by random attempts.

ok got the new mosfets but after install not getting any voltage at all?? not even at the dc jack ?? Maybe they sent me wrong ones and i blew something else?

[mon2]

Re: Asus Rog Laptop new battery still 0% Biard issue?

Remove the power adapter. Meter in dc volts mode. Use a 20v or higher scale.

Red meter probe to inside of the adapter barrel / coax connector. Black meter probe to the outside of the same connector. Plug in the adapter to the wall.

Do you have ~19v dc volts reading?

If yes, remove all power. Meter in resistance mode. One meter probe to the center pin connector on the logic board. Other meter probe to ground.

What is the resistance?

[irepair559]

Re: Asus Rog Laptop new battery still 0% Biard issue?

im getting 20v out of the charger..

OL For center dc jack and ground
1 ohm for center dc jack and coil right next to it..

But at the dc jack just 0.5v and dropping till zero

seems like charger goes into safe mode and kills the voltage on the charger due to some short or issue on board...

i put back original mosfet and same issue.. bummer

at least before it would power on now board is dead ����

I think those new mosfets are wrong type and damaged something?