Thanks again. I know that Lenovo would go with motherboard replace (I was considering it myself too, but the MB costs 70% of the price we paid for the notebook back in 2021), that's why I contacted the electronics service recommended by someone I know. I said exactly what the issue is and that probably EC is burned and they say that the diagnosis is free and the repair cost wouldn't go above $120, which I thing is a fair price that make this repair worth it.
I will update this thread when I get the notebook back. Maybe it will be useful for someone in the future....
gleniu
Member
Last Activity: 11-28-2025, 05:06 PM
Joined: 11-13-2018
Location: Świdnica
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I decided to go with a professional service. I'll update on what was the exact issue when I get the details.Leave a comment:
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I've spent some time trying to figure out what is the correct pinout on the DC jack and it seems that the signal one you mentioned is the middle one - see the image attached. I've also measured the power adapter plug and it definitely gives 19V on the side inner connectors, but not on the center one. Don't get me wrong, I'm not trying to correct you, I'm just trying to make sure that I didn't blow up the EC by using defective power connector.
So I'd say that the expected measurements on power connector are as follow:
1 - GND
2 - APDIN - 19V here
3 - N21106349 - the...Leave a comment:
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Thank you very much for your response. I just want to clarify a few points (this really shows my lack of experience and theoretical knowledge). Before installing the new socket, I plugged the charger into it and checked the voltages on the individual pins, but it did not occur to me to check where these voltages should actually appear – I simply did not assume the new port was faulty. According to the boardview, the power jack has the following pins:
1 - GND
2 - APDIN
3 - N21106349
4 - APDIN
5 - GND
6 - GND
7 - GND
In my measurements, there was...Leave a comment:
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Lenovo IdeaPad Gaming 3 15ACH6 - no power
Hi, I have a problem with a Lenovo IdeaPad Gaming 3 15ACH6 laptop. My nephew asked me to replace the charging port because the laptop wasn't charging. This issue had happened in the past, so I knew that replacing the port was only a matter of time. Until now, my nephew managed to deal with the problem using a temporary solution: bending the positive metal tabs inside the port with a thin tool. However, this had stopped helping for a while. Today, I replaced the port – and to my surprise, after the replacement, nothing happens when I plug in the charger: the power LED doesn't light up, the laptop...
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Well, that's disappointing but expected
Thank you so much for help, guys!Leave a comment:
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After I removed PLA1 only, main power rail (probe PRB46) showed 10,2Ω to ground.
When I removed PQA1 mosfet as well, the short was gone.
It still shows short to the PLA1 pin, the closer to CPU one.Leave a comment:
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Thanks, I will try to find some time tomorrow to desolder PLA1 and PQA1 and will report back.
Also, it turns out that my colleague has a thermal camera, so I might end up getting an adjustable power supply and look for the element that gets hot.Leave a comment:
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I don't have adjustable power supply, unfortunately. I might get one, because I need it more often than I'd expect. Any recommendations from Aliexpress?
For now - is it possible to use anything else for that? I guess using 1,5V AA battery for it is a stupid idea, isn't it?Leave a comment:
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mon2, sorry for confusion. I thought that was the case - in fact this my son's notebook and this was his version. Lesson learnt - never trust kids
But back on topic - I don't think the measurements look good:
Inductors to GND:
- PLG1 - 7.4Ω
- PLZ1 to PLZ4 - 0.2Ω
- PLA1 - 0.1Ω
- PLH1 - 0.6Ω
- PL1001 - 14.2Ω
Inductors to main power rail (I used PRB46 as 19V contact point - hope that is ok):
- PLG1 - 7.4Ω
- PLZ1 to PLZ4 - 0.4Ω
- PLA1 - 0.1Ω
- PLH1 - 0.6Ω
- PL1001 - 15.2Ω...Leave a comment:
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Hi mcplslg123, thank you for your input.
I'm affraid you might be right. I've checked the resistance to the GND from PRB46 and it shows 0.1Ω (on both sides).
So probably MOSFETs got destroyed by a short caused by something else, just as you suspected.
Any noob-friendly step-by-step guide on how to try to find the shorting element?Leave a comment:
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Actually, I found a store (TME.eu) that has AON7380 in a very good price. They also have AON7318. Which one would you recommend?
I see that PQB11 is EMP21N03HC, which I was about to replace with MDU1511. That store doesn't sell MDU. Any replacement from AON? For example they have:
- AON6512
- AON6560
- AON6500
I only checked 115A and higher, because the datasheet I found for EMP21N03HC says that its drain current is 100A, but I'm not sure if that's true. They also sells lower currents from AON.Leave a comment:
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AON7380 did the trick - it is not sold by the store I'm about to order MDU1511 from, but I can order it for a little price from a different seller.
So, to sum up, I will order:
- AON7380 for PQB12
- MDU1511 for PQB11
I will do it now, when it arrives I will attempt a repair, hopefully the PC will boot. I will update the thread for sure. Thanks!Leave a comment:
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I probably have some other options, but honestly I'm lost as how to look for these I'm using AI for finding replacements, then I looked through the store where I'm about to order MDU1511. I probably ask for too much, but would you be able to take a look at this store offer to check if there is anything suitable?
https://mikrusy[dot]pl/szukaj.html/szukaj=chip
For some reason they name all the mosfets CHIP, which also doesn't make it easier to look for these.
I will try to look for replacement by myself as well. If I find something, I will post here....Leave a comment:
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Yes, it is definitely smaller and it is PQB12. I have just removed it. It seems to have 3x3mm in size.Leave a comment:
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Thank you, so I need to order a replacement for it. Will SIS412DN be a good replacement for B09N03?Leave a comment:
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Also, the power adapter doesn't short now, with the MOSFET removed....Leave a comment:
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The measurements of the second MOSFET in resistance mode:
1. Red probe on source, black probe on drain: 64.8Ω
2. Black probe on source, red probe on drain: 106.4kΩ
3. Red probe on gate, black probe on source: OL
4. Black probe on gate, red probe on source: 53.2kΩ
5. Red probe on gate, black probe on drain: OL
6. Black probe on gate, red probe on drain: 105.2kΩ
I think that this one looks good and we're close to saying for 100% percent that the PQB11 is the culprit, aren't we?Leave a comment:
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The measurements of removed MOSFET in resistance mode:
1. Red probe on source, black probe on drain: 0.1Ω
2. Black probe on source, red probe on drain: 0.1Ω
3. Red probe on gate, black probe on source: 1.00kΩ
4. Black probe on gate, red probe on source: 1.10kΩ
5. Red probe on gate, black probe on drain: 1.00kΩ
6. Black probe on gate, red probe on drain: 1.10kΩLeave a comment:
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Thanks, I managed to put it in place.
Is it a good idea to plug in my DC adapter with MOSFET removed just to check if it still shorts? Of course I won't be powering on the machine, anyway the motherboard is completely out of notebook's body now.Leave a comment:
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