DH5VF LA-F952P Motherboard short circuit

[247]

Hello dear community,

I have the following damage to an ACER AspireA717-72G, and I had a short circuit, attached are pictures of the damage.

It's about the DH5VF LA-F952P motherboard.

I will try to change the 3 transistors (2 marked red and one marked blue) and see if it comes on again. Can you tell me what the parts are so I can order them?

I can solder but I'm not familiar with the construction plan of the mainboard, do you think it still makes sense, or can the mainboard be thrown away?

Many thanks for the support

[lotas]

Re: DH5VF LA-F952P Motherboard short circuit

These are not transistors, but ceramic capacitors, you will understand their denominations on the diagram.

[247]

Re: DH5VF LA-F952P Motherboard short circuit

These are not transistors, but ceramic capacitors, you will understand their denominations on the diagram.

Thanks for your pictures.
I found these.

https://www.mouser.de/ProductDetail/...3D&mgh=1&vip=1

are they correct

Unfortunately, I haven't found the PC1302 yet.

[247]

Re: DH5VF LA-F952P Motherboard short circuit

These are not transistors, but ceramic capacitors, you will understand their denominations on the diagram.

Hi, I have such a set, can I take the 2 with 6.8k? For 10U_0805_25V6KPC1304 and PC1310?

Can I take something from the table for PC1302 2200P_0402_50V7K? Or is there no right one?

[Adenitz]

Re: DH5VF LA-F952P Motherboard short circuit

If you have a short, then most likely only one component is shorted. You need to find which one and to remove only that one. Otherwise if you just start to remove all components you find "shorted" then it can take a lot of time and a lot of component.
When one capacitor gets shorted on a power rail, many things that are on that rail can appear as shorted.

[247]

Re: DH5VF LA-F952P Motherboard short circuit

If you have a short, then most likely only one component is shorted. You need to find which one and to remove only that one. Otherwise if you just start to remove all components you find "shorted" then it can take a lot of time and a lot of component.
When one capacitor gets shorted on a power rail, many things that are on that rail can appear as shorted.

Did you see my pictures above? I wanted to change the ones that are locked, but I don't know exactly which ones they are

[lotas]

Re: DH5VF LA-F952P Motherboard short circuit

Hi, I have such a set, can I take the 2 with 6.8k? For 10U_0805_25V6KPC1304 and PC1310?

Can I take something from the table for PC1302 2200P_0402_50V7K? Or is there no right one?

10U_0805_25V6KPC1304 and PC1310 - Do you have these

2200P_0402_50V7K PC1302 - You don't have this

[247]

Re: DH5VF LA-F952P Motherboard short circuit

10U_0805_25V6KPC1304 and PC1310 - Do you have these

2200P_0402_50V7K PC1302 - You don't have this

Is that the correct one?

https://www.mouser.de/ProductDetail/...jYzssoag%3D%3D

Only find the ones here to buy.

https://www.mouser.de/c/passive-comp...%20dc=50%20VDC

Thanks for your support

[lotas]

Re: DH5VF LA-F952P Motherboard short circuit

Is that the correct one?

https://www.mouser.de/ProductDetail/...jYzssoag%3D%3D


Thanks for your support

Yes

[lofaszjancsi]

Re: DH5VF LA-F952P Motherboard short circuit

A (somewhat) funny coincidence is that my Acer A715-72g died too. It seems that i have a bad mosfet as show on the attached picture.
My question is that what else can be bad if this mosfet died? (No visible damage on the board)

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Good day everyone,
I also have Acer board which works normal with only charger without battery.
It also works normal with only battery without charger.
But if battery and charger are connected together the system will short at the DC reading and the screen will be displaying abnormally. I've used another battery to confirm but same thing.
I've checked the impedance of first and second MOSFET and likewise battery MOSFET, everything is free of short.
Kindly help because I don't know what to check again.

[mon2]

Re: DH5VF LA-F952P Motherboard short circuit

Hi. You should start a fresh thread.

Review the other mosfets tied to the charger IC as they may be leaking. With no power, review the resistance across the mosfet pins for the battery mosfet (pq312) and also the high side mosfet (pq305).

As a quick test, remove pq312 and power up with only the external power adapter. It should work like normal.

Then power down and attach the battery. Power up again with the external adapter. Logic board should still power up like normal since the battery mosfet is removed and should not interfere with the power path.

You can use the attached schematic as a reference that should be similar to yours.

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Thanks so much for the great response I did as you said but same thing still persist.
Almost all the time the lower MOSFET of the battery used to be very hot when I plugged the battery and charger.
But thank God I later solved the case.
Its the gate voltage of the switching MOSFET that was not generated.
Immediately its generated the case was solved.

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Good day to u all.
Pls I have dell board LA 7901p
Power on to 0.15 on DC ready and reduced to 0.12after view seconds and constantly repeated.dc
I've programed bios but same thing.
DC 1.5v, 5v, &3.3v present.
Second MOSFET gate pq1300 is 0v, can this cause the problem.
Thanks

[mon2]

Re: DH5VF LA-F952P Motherboard short circuit

What are the topside markings of the 2nd DCin mosfet?

Which charger IC is onboard?

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Thanks for great response sir.
I don't understand the topside marking sir.
The charging ic is ISL88731C
Thanks so much sir

[mon2]

Re: DH5VF LA-F952P Motherboard short circuit

What is the part number of the 2nd mosfet?

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

Thanks boss man.
Pq1300

[mon2]

Re: DH5VF LA-F952P Motherboard short circuit

See attached for a typical ISL88731 charger based design.

The 2 x DCin mosfets are P-channel style. So this means the mosfet will turn ON if the GATE voltage is LOWER than the voltage being passed between source / drain pins.

So if GATE is 0 volts, this is OK.

Of more concern is if this mosfet is leaking.

Remove all power -> meter in resistance mode.

Measure the resistance across this 2nd mosfet:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post each measurement and the meter scale used for the checks.

[Oj computer]

Re: DH5VF LA-F952P Motherboard short circuit

thanks sir
Source (123) =381ohm
Drain (5678)=493ohm
Gate=549ohm