Asus Eee PC 1005PE the battery isn't charging

[samtron786]

Hello everyone
Hello, the problem is that after connecting the power adapter, the power supply flashes and doesn't charge the battery. Interestingly, it's causing a short circuit. So I decided to open the notebook to check. I'm missing the circuit diagram.
Greetings
Thank you very much

[mon2]

Test with a known good battery. Source one from Amazon or similar and return it if it is not required.

[samtron786]

Yes, I already ordered one, unfortunately, the same problem.

[samtron786]

The same problem with both batteries, and I have to remove the battery. The laptop turns on without the battery. Then I have to put the battery in the laptop to charge it. Otherwise, it won't work.

[mon2]

Locate the charger IC on the board and share the topside markings. We can then locate a reference diagram or datasheet for this charger IC to study what should be similar to your logic board. Often, the charger IC is from BQ = Texas Instruments. If not sure, just take a few pics of all square (QFN) packaged IC on your board. The charger IC should be nearby the DC in connector and also close to the battery connector.

[mcplslg123]

U mean you connect charger first and then battery and it charges fine? And if battery is put first and then charger,it dont charge? Right?

If so, fault lies in dc-in mosfets and/or discharge mosfet.

[samtron786]

EMB24B03G PQ1

EMB20P03V PQ2

[samtron786]

U mean you connect charger first and then battery and it charges fine? And if battery is put first and then charger,it dont charge? Right?

If so, fault lies in dc-in mosfets and/or discharge mosfet.

Do you mean if you connect the charger first and then the battery, it charges perfectly? That's exactly how it works.
And if you connect the battery first and then the charger, it doesn't charge? Is that true? Yes, that's true.

[mon2]

Remove all power. Meter in resistance mode. Not diode mode.

Measure the resistance across the mosfet:

source & drain
source & gate
gate & drain

each measurement must be hundreds of k ohms or higher else is a suspect.

[samtron786]

S1
Source & Drain .291 MG
Source & Gate 99,7 Kohm
Gate & Drain .392 MG

S2
Source & Drain, 00,4 Ohm
Source & Gate, 37,2 Ohm 50,0 Ohm
Gate & Drain. 36,2 Ohm

[mon2]

They both look bad but S2 is definitely shorted. Flux and remove the S2 mosfet and test the same when the part is on your work table. When S2 is removed, test the resistance again on S1. If the measurements remain to be similar, also replace S1 mosfet.

[samtron786]

I have two more pieces here exactly the same

S1
Source & Drain, 64,2 Kohm
Source & Gate, 36,0 Ohm
Gate & Drain. 60,0kohm

S2
Source & Drain, 01,4 Ohm
Source & Gate, 36,5 Ohm
Gate & Drain. 38,5 Ohm

S1
Source & Drain, .2,36 K Ohm
Source & Gate, O.L
Gate & Drain. O.L.
S2
Source & Drain, 00,4 Ohm
Source & Gate, 30,3 Ohm
Gate & Drain. .350 MG 30,3 Ohm

[samtron786]

I only wrote to you about one. EMB24B03G
Dual P‐Channel Logic Level Enhancement Mode Field Effect Transistor

I'm now writing to you about a P-Channel Logic Level Enhancement Mode Field Effect Transistor.
EMB20P03V
B20 P03


Source & Drain, 66,4 K ohm
Source & Gate, 19,7 K Ohm
Gate & Drain. .570MG

[mon2]

Each of the posted S2 mosfets look to be defective. Flux and remove them and then test their resistance when they are no longer soldered to the board.

Very likely, the resistance readings will be similar and the parts are indeed defective. Proceed to test the S1 parts after S2 is removed. Perhaps S2 is influencing the low readings on S1. If S1 readings are still low, replace them as well.

The same test method can be used to diagnose other mosfets linked to the charger IC.

[samtron786]

OK, I'll do that right away. If they're defective, can you please suggest which ones I should buy and order?
Thank you.

[mon2]

Can you confirm that for the DUAL P-channel mosfet, you have indeed measured the resistance across each leg as requested?

The posted S1 and S2 measurements are for this single device?

Internal view of the dual mosfet:



The PQ2 mosfet is a single P-channel mosfet which is also low in resistance.

Are you ok to purchase from Digikey? It will be faster to receive goods from Digikey or Mouser than Aliexpress. If you not in a rush, Aliexpress will be cheaper.

[samtron786]

Do I need to look for the same MOSFET, or can you recommend one?
Thanks

[mon2]

No, you can replace with a suitable or perhaps even better rated parts for each mosfet on the board. Are you in a rush? If yes, Digikey or Mouser may make more sense. Even faster if you have access to a donor board for at least testing out the repair process of one board. If you are ok to wait, consider Aliexpress.

Can you share the details from post # 16? Wish to be sure we are indexing the same parts. The measurements are very low so you have a defective mosfet.