Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

[corrize]

Hello,

2sd high side mosfet was shorted, and replaced. ok.

Now, all is good (I have another exactly same MB working for compare), except a low voltage drop on mosfet of buck converter, close the ram. 0,150v instead 0,450v for working MB.

I removed this mosfet, and no change, the 0,150v stay on the coil pad (ram side).

In following direction of 19v power rail : voltages drops are fines. But in ram direction, at all caps around ram modules, I measuring (of course) the same voltage drop than the coil.

I guess the internal power line of ram modules could be bad ? Do you see another explanation pls ? How to check ?

If I temove the two other mosfet close the coil, ram should be fully isolate from power lines ? And if voltage drop is the same, that means the ram internal power lines are broken ?

I worked only without power, maybe the MB works. But I'm scared to try wuth this issue.

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

Upsate : maybe found another guilty candidate ?
The 20 pins chip close the coil (up-left) is a ram power controller RT8248A
It has 2 pins at 0.150v instead 0.300v. I will see the lines on datasheet soon.

Do you have a method for check wich chip is faulty in this case of low voltage drop pls ?

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

Update : I desoldered the 3 mosfets and controller chip (see attachlent), and the same.

Resistance and voltage drop (diode mode) coil to ground are 2x lower than good board.

Ram zone of MB seems isolated now. The mosfets inputs are ok (voltage drop are the same on the good board).

Is it possible to déduce this low voltage drop come from ram module ? Damaged internal power line ?

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

Or maybe there is no issue ?
I measured on 3th Asus (a dead one), on same ram power controller chip, same low voltage drop. So maybe it’s « normal ».
I will resolder all and try to power on. At worst, if something burn, maybe that will do a true short.

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

Hello, I'm back on this motherboard.
(All I writed before is useless, I compared two same boards for find differences without power).
I just replaced the high side mosfet that was shorted.

First time I plugged the charger, I saw a first unexpected issue : the jack connector soldered on motherboard has a « clic » position when the jack is fully plugged. And this clic is necessary to pass the current. On this one, the « clic » is broken, so I fully plug the jack, but I feel no clic and the current don't pass. First time I see that on laptop. But no the problem, I just have to replace the connector.

Yesterday, I plugged the PSU and I had a light on power on button. And when I pressed it ; nothing happened.
I measured 5v at 5v coil.
I plugged battery and not charging.
PSU consumption : 110mA
I felt little heat around processor, but probably not the proc itself (there is no coil shorted).

This morning, I tested again and big change :
The second high side mosfet (that I replaced) heating
With battery removed, PSU consumption : 1.2A (max allowed on PSU for this test)
So there is a short somewhere (no coil shorted).

I started a new diag (PSU off), but I don't found a short on and around high side mosfets. They seems good. I can't understand how to a mosfet can be warm and not shorted.
Do you have an idea to what to check after pls ? The charging chip ?

Another weird thing : I can't find the 3v 5v chip on the board. I guess there is not, and these voltage are provided by two buck converters. It is possible ?

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

I checked again all around 2 high side mosfet ; no short or low resistance, all combinations : source-gate-drain… All combinations are around 50KOhms or OL. No short no low resistance. The same around. The same to ground.
The input jack has a 100kOhms resistance. The same for all the line 19v.
At the shunt resistor, to ground, in diode mode : 0.5v so good, and >100kOhms to ground.
At the Vcc pin at the charging chip ; no low resistance.
The same at all coils : no low resistance and no short.
And yet, when I put PSU with 19v 1.2A to jack, the PSU show colapse to 0.4v 1.2A consummed, tyhe 2sd mosfet heating and I measure on some coils ; 0.4v (so current leak from mosfet, or charging chip I guess ?)

So, I'm in the fourth dimension ; I can't understand how the 2sd mosfet can be so hot with no low resistance or short around it ? It is not possible.
If there was a component shorted on motherboard, the mosfet should be in « blocked » state, but in « open line state ». It can't be in « short circuit state » for « blocking » the current.

Maybe the lone explanation could be that the mosfet (1st or 2sd) is faulty (short circuit) when it is in « blocking » state, and leaking a little in this state ?

[rediii]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

I checked again all around 2 high side mosfet ; no short or low resistance, all combinations : source-gate-drain… All combinations are around 50KOhms or OL. No short no low resistance. The same around. The same to ground.
The input jack has a 100kOhms resistance. The same for all the line 19v.
At the shunt resistor, to ground, in diode mode : 0.5v so good, and >100kOhms to ground.
At the Vcc pin at the charging chip ; no low resistance.
The same at all coils : no low resistance and no short.
And yet, when I put PSU with 19v 1.2A to jack, the PSU show colapse to 0.4v 1.2A consummed, tyhe 2sd mosfet heating and I measure on some coils ; 0.4v (so current leak from mosfet, or charging chip I guess ?)

So, I’m in the fourth dimension ; I can’t understand how the 2sd mosfet can be so hot with no low resistance or short around it ? It is not possible.
If there was a component shorted on motherboard, the mosfet should be in « blocked » state, but in « open line state ». It can’t be in « short circuit state » for « blocking » the current.

Maybe the lone explanation could be that the mosfet (1st or 2sd) is faulty (short circuit) when it is in « blocking » state, and leaking a little in this state ?

nevermind, sorry

[Stevedb]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

Did ypu try with original charger too. Which charging ic do you have how much do you have at the gate from the second mosfet. Did you yest mosfet out the circuit?

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

nevermind, sorry

No idea, you meant ?

Did ypu try with original charger too. Which charging ic do you have how much do you have at the gate from the second mosfet. Did you yest mosfet out the circuit?

I have the originale charger but I can't plug in, because there is a « clic » position deep on jack connector on MB, and it is broken and current is blocked. So, I can plug the jack of charger fully in connector (with 19v measured ok before and after), but nothing come on the motherboard. I need replace this connector.
So I have only the PSU for testing, and anyway, I guess it is not a good idea to increase current, something will burn.

My (new) hot air station is dead ; it provide only 340 degrees. I tryed but the mosfet don't move. I will retry with solder iron in help.

[mon2]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

The mosfet may not be moving due to heavy ground plane on multilayer pcbs. You are likely facing a 6-8 layer pcb. Do consider to purchase an underside IR heater from AliExpress or similar. Together, you will be able to remove this and other parts. Check youtube for examples on its use.

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

Update : hot air repaired, I removed the 2sd high side mosfet and compared, it has a leak : S-D = 3M Ohms, and the 1st high side has a such leak too.

To replace this 1st high side mosfet, I have a new one in stock (from gamer laptop) and I don't know exactly if it can match ? Which are very important pls ?

The twice are N channel and the main value is the same : Vds : 30v. But I don't know for other specs :

UX433F to repair---------------------------------------------In stock (gamer)
M3056M------------------------------------------------------B04N03
Drain-source voltage : 30v----------------------------------30v
Gate-Source Voltage : 20v----------------------------------20
Continuous Drain Current (at 25 degree) : 100--------- --75
Pulsed Drain Current : 300----------------------------------160
Avalanche Current Pulse (Ias) : 36------------------------- 53

This one in stock seems has lower specs, but it go on the 2018 gamer laptop : 15', i5 and GTX1050. And the UX433F is 2019 14', i5 « U » model so low power, and no graphic card. So for power considerations, gamer laptop mosfet should be ok for this little laptop ?

[mcplslg123]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

S-D resistance of 3M ohms and you consider it as a leak?? Think twice before proceeding with un-necessary steps.

Btw, the mosfet you listed is not suitable as replacement as Pulsed DRian Current has a huge difference.

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

Thanks, I need another one so.
This is the 1st high side mosfet.
I recently replaced the 2sd mosfet by a new one (same model), and the laptop worked (not completly) a little bit and stoped working and this mosfet heating. I desoldered it and compared with an another new one, and there is a difference (3M Ohms instead open line), so it is damaged. Yes, it is a little difference, but in working ?
And the twice have a same leak issue. I don’t want to have doubt about mosfets for continue the diagnose.

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

Update : I replaced by a mosfet in stock for search where come from the heat I felt before it be shorted. And the heat come from PCH. Not good. But I can't find short under PCH at capacitors, no coil shorted and nothing shorted nowhere. So, according all the measurments, I see no reason that it is shorted.

The big problems are test conditions : if I test with full power : 19v, 3A, I can test if the board start or charging but I'm scared the chipset heating more and blow up. And the last time I tested with 1.2A, the 2sd high mosfet has burned and shorted.

So I limited PSU at 19v, 600mA, maybe too low for testing motherboard start ? But the voltage don't try to grow up and the motherboard consume directly 100mA and keep stable.

At least, it is stable for taking some measurments.

I tryed to measure IC charging to continue the diagnose but noticed nothing obvious. Maybe TB_STAT : 0v ?

So maybe the board works, I have 5v, 3.3v the next step should be try with more power for testing starting, but I'm scared. Do you know how to test safely pls ?

Charging IC (BQ24780) (no batt)

1 - ACN : 19.4v
2 - ACP : 19.4v
3 - CMSRC : 18.9v
4 - ACDRV : 24.4v
5 – ACOK : 5.96v
6 – ACDET : 2.64v
7 – IADP : 0v

8 – DCHG : 0v
9 – PMON : 0.17v
10 – PROCHOT : 5v
11 – SDA : 3.24v
12 – SCL : 3.29v
13 – CMPIN : 0.2v

14 - CMPOUT : 6v
15 – BATPRES : 6v
16 – TB_STAT : 0v
17 – BATSRC : 3.25v
18 – BATDRV : 0.22v
19 - SRN : 0.22v
20 – SRP : 0.22v
21 –ILIM :1.16v

22 - GND : 0v
23 - LODRV : 0v
24 - REGN : 6v
25 - BTST : 5.84v
26 - HIDRV : 0.22v
27 : PHASE : 0.2v
28 : VCC : 19.4v

[Sephir0th]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

Honestly,

I'm not sure where to start here but basically it isn't a good idea to try to repair a motherboard with this degree of missing knowledge about the how to.

For me it is still not clear what do you mean with "2sd high side mosfet". Also you completely miss the basics:

a) When the controller for the memory isn't supposed to work (missing enable for example) Then you of course won't get any voltage from there.

b) You're saying "no shorts found" but regarding what you have shared here so far we can't trust in anything. For proper troubleshooting we need the resistance measurements of each power rail. I guess you missed that your main power rail was shorted with a secondary rail, at least for a While. which brings us to

c) you have injected 19V(!) Into the Main power rail without knowing with What you're dealing here, so your device is possibly already a ready for donor purpose.

Same with d) if you want to make a new donor board, then you power up a board with missing components, especially mosfets, like you did.

You wrote tons of sentenses here and we still don't know anything about the situation of the board. So what Are you expexting? You need to work in a Systematic way to troubleshoot the board properly. You'll never be able to find the issue otherwise. So go ahead and come back with tons of measurements implemented in pictures of your board.

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

I did an electronics school for 4 years, and I worked some years in electronics design labs (but I didn't like that).
So I have the basis. But yes, I'm beginner for laptops repair, smd components and micro soldering.

As I said in first post, I troubleshoot only power off. And when there is no more anomaly in measures, no short and no low resistance could damage component, I check if it works with power.

I didn't power up the board with missing component.
The « second high side mosfet » is the second one at the jack connector.

The RAM memory controler was a wrong way in this troubleshooting. It should be ok.
And now all should be ok on the board. It's a test to check that.

The current situation is special and need experimented advices I guess : I want to be safe, I don't yet tested if the laptop start with more than 1.2A. Maybe it is too low for start (or charging when I plugged the battery) ?

I'm now testing with PSU limited to 600mA (no batt), because as I said :

1 - the PCH is hot but not burning so it can just… working ? But it consuming 100mA, that seems too high.
2 - and because at the previous test at 1.2A the 2sd high side mosfet (at jack connector so) has failed (not instantly, after 1 day while laptop didn't start). But I measured no short or low resistance nowhere in the board after.
3 – and because limited at 600mA, I expected testing the « stanby power off state » before pressing power on button, so I expected a stable and very low standby consumption of around X mA.
But no, the consumption start at 100mA and after few seconds grow up at 110mA and keep stable.

Good idea for measures at coils :
3.3v, 5v ok
1.04v at two coils above PCH : +1.05VSUS and +VCCSA
1.8v : +1.8VSUS
0.2v at charging battery coil (P_CHG…) no battery plugged
And 0v to all other

[Sephir0th]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

A bit of offense taken was calculated in my post to find out with "who" we're dealing here.

A DC-IN Mosfet has neither a high side nor a low side, since it can't be compared with a buck converter but in this point you're right and it gives me hope: The electronics basics are present. However we have a big issue with the methods and the way of troubleshooting here. So we're lost in tons of useless measurements and observations here. Also it seems like you're overcomplicating the things since you assume some kind of "special" fault which probably isn't the case here.

Also you're still persisting on your way of troubleshooting instead of just asking here what could be the best and especially the easiest or fastest way.

But it seems we make some progress now. From voltage measurements the RAM supply should be indeed present, because even +VCC_SA is present which usually come up at the same time (or even later) in the sequence.

So yeah maybe the Memory rail has an issue, maybe not. We have still to less informations, especially about the health of the various power rails. So please add resistance to GND measurements of all important power rails (at the coils and at the current sense resistor of the main power rail). And maybe worth to take a closer look to the memory controller, so input voltages and enables to start with.

Btw: a somewhat "hot" PCH in working condition (3.3V and 1.05V present) is a absolute normal behaviour.

However I wouldn't inject any voltage into this board as long as it is not clear in which area is the fault and with what possibilities we're dealing here.

Best regards

And before I forget: limiting the current won't save the board from anything bad. It is the voltage which kills the components, not the current.

[corrize]

Re: Asus Zenbook UX433F I5 – battery connector metal clip dropped on MB

Repaired, works fine (not yet tested all but start and charge), the issue came indeed of chip driving the switching power supply of RAM memory. Thanks for the help.

Left to find a new DC jack connector, there is a weird switch inside, I will probably order it to the Asus parts website, do you know if it could be found elsewere pls ?