You have a keen eye, I missed that. Yes those two components were bridged at the top there. I have removed the bridge with wick and flux.
Laptop still does not turn on or charge. Would that bridge have damaged the charging ic?...
gadgettree
Member
Last Activity: 01-03-2025, 02:35 AM
Joined: 02-23-2022
Location: Sooke BC
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Alright, so I have reflowed the charger IC and it is still doing the same thing.
[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3235134}[/ATTACH]
I know it's not the best picture, as pressing the capture button without shaking the microscope is difficult. But I am confident it is on there properly.
Could it be anything else, or is this still the most likely culprit.Alright, so I have reflowed the charger IC and it is still doing the same thing.
[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3235134}[/ATTACH]...Leave a comment:
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What laptop is it. Specifically what model. Can you find the board model?Leave a comment:
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I have reflowed the charging ic a few times. I'm very happy with it at the moment and would be quite surprised if it wasn't soldered on properly at this point. The DC-IN MOSFET as well. I made sure pin 1 of the bq is oriented correctly, as well as the MOSFET.
That being said, I definitely need more practice so I will leave it for a couple days and try again.
Currently it's still not charging or powering on.
Leave a comment:
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PQB1 has been removed, the result is the same. 0V on Pin3 of the charging controller.Leave a comment:
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The resistance is correct between the common junction and pin 3 (4.02KOhm).
I will go over my soldering of the charging controller and see if I messed that up.Leave a comment:
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PRB4 Resistance: 4.8 Ohm
PRB7 Resistance: 4 KOhm
Resistance to GND of charging controller pin 4 is 1.9MOhm which I am assuming is fine.
I had already ordered the BQ chip to replace on this guy just in case, so I have replaced it but it still doesn't charge, nor is there a voltage on the Gate for PQB3.Leave a comment:
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Okay. Part came in yesterday and I have soldered on the new Mosfet. I found the same part on LCSC so I used that. The resistances are all in the megaohm range now, so the defective part has been replaced with one that works. The laptop still does not turn on or charge.
There is still not a voltage at PQB3 Gate, so perhaps something is wrong with the charging chip as Sephir0th suggested.
I have done some measurements around the BQ chip, but I don't really know too much about what I should be looking for, or which measurements matter. The only one I really understand is ACDET...Leave a comment:
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Awesome. I have ordered a replacement mosfet and I will let you know when it works.
Thanks for your help, I have learned a lot.Leave a comment:
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While PQB4 is still soldered on the drain to ground resistance is odd. It starts with a very low resistance of about 5kOhm and rises to about 50kOhm over about 30 seconds. Maybe my multimeter is charging some capacitors while measuring for resistance?
After removing PQB4:
PQB3 Measuring source and gate resistance I get 2.3MOhm
PQB4 Motherboard Pads Source and Gate resistance I get: 3.3MOhm
PQB4 mosfet source gate resistance: I am having trouble measuring source and gate pins with my probes, even under my microscope. Is it safe to say the Mosfet...Leave a comment:
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Thank you for the response mon2.
I have taken the measurements as requested and I am not seeing a short at all. I am noticing there is no voltage present at all at the gate of input mosfet 1.
The measurements are as follows, and a picture for reference.
Voltage at PQB3 Gate is 0V.
Removing the power and measuring resistances now.
PQB3:
Source and drain: 3.3MOhm
Source and Gate: 24.1kOhm
Gate and Drain: 3.3MOhm
PQB4:
Source and Drain: 2.89MOhm
Source and Gate: 24.1kOhm
Gate and Drain 2.92MOhm...Leave a comment:
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Acer Nitro AN517-52 FH51M LA-J871P Works on battery only. Won't charge.
Hi there,
I am having trouble diagnosing this gaming laptop.
The laptop does not power on with AC Power only. The battery also does not charge. The laptop turns on when the battery is plugged in, regardless of whether or not the charger is plugged in until the battery dies of course.
So something is stopping adapter power from getting to the laptop. I checked Adapdet to make sure that the motherboard knows when the adapter is plugged in. That works fine.
I suspect the first Mosfet isn't turning on but I am unsure how to properly diagnose that... -
Hi, long time lurker. Never saw the requirement for new members to post in this thread so I'll do that now.
Getting into board level diagnostics as I believe it will be necessary in the future for repair shops to survive. Things are becoming less serviceable over time without board level skills.
Thanks to everyone who posts here and shares knowledge. I feel like I have learned a fair amount so far.Leave a comment:
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