I gambled and bought a new battery (traveled like 40 days π
). It came partly charged and when i plugged it in, the laptop came on.
- If it's on AC, it shows the charging sign,[B] but it does not charge.[/B]
- If i unplug the AC adapter, it stays on.
So now the only thing left to solve is the battery not charging issue. How would I go about this?I gambled and bought a new battery (traveled like 40 days π
). It came partly charged and when i plugged it in, the laptop came on.
- If it's on AC, it shows the charging sign,[B] but it does not charge.[/B]
krayz
Senior Member
Last Activity: 04-19-2025, 04:21 PM
Joined: 11-19-2021
Location: Kamnik
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Update with additional info:
- Now the laptop behaves like this:
-AC and battery plugged in -> Battery 0% and charging, but in reality it is not, constant 0%.
-AC only, battery unplugged -> "Battery fully charged" (??), and not charging.
- I can charge the battery with LabPSU. Checking with the multimeter DC mode, red on red, black on black, i'm not getting any reading. Checking the cells themselves, i get 3V on both of them.
- Plus pin of battery connector to GND when connected to AC shows ~0,86V
Also, the...Leave a comment:
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Sometimes stubberness pays off
I checked PQ8901 (in the previous post i wrote incorrectly, voltage drop was 0,14V) off the board and it was OK, S-D voltage drop 0,5V and normal resistances. Then PQ8902 started having voltage drop S-D 0,14V. So i put PQ8901 back, since it was good. Not sure how to proceed.Leave a comment:
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Another problem emerged:
- there is a power led sequence, but i couldn't find the meaning: 1 long white blink, 1 short orange blink -> 4 times, then boot
- the laptop works while plugged in with battery disconnected.
- it also works while plugged in with battery connected, but here windows shows "Battery fully charged", which is highly unlikely. It turns off instantly when unplugging;
- it DOESN'T work on battery only
Here i found PQH8901 is giving me inconsistent resistance measurements and a S-D voltage drop measurement...Leave a comment:
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It would seem I have found the issue: A 1M resistor PR8922 was blown. I replaced it and, to great joy, was greeted by the Asus loading screen. I'll test around some more to see if everything is in order.
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3579529}[/ATTACH]βIt would seem I have found the issue: A 1M resistor PR8922 was blown. I replaced it and, to great joy, was greeted by the Asus loading screen. I'll test around some more to see if everything is in order....Leave a comment:
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I searched further and found that i have 3VA, but i don't have 3VA_EC, i'm guessing that's why it isn't turning on. Can't find the cause though. Also, isn't 6V for ACOK too high?Leave a comment:
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As i was checking the components on the line, I discovered something else as well. It would seem I blew off a component when replacing the BQ: [B]PR8912.[/B]
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3578936}[/ATTACH]β
I replaced it with a resistor with the value taken from the boardview (100k). Now the ACOK pin gets 6V. The laptop is not turning on though (with just the adapter plugged in). So... don't know if this is progress or regressAs i was...
Leave a comment:
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I've measured PQ8905A (N-MOSFET EM6K1GT2R EMT6) as well. Resistance mode, no power. With both probe polarity. [TABLE="border: 1, cellpadding: 1, width: 300"]
[TR]
[TD]red (1) & black (6)[/TD]
[TD]250 kOhm[/TD]
[/TR]
[TR]
[TD]red (2) & black (6)[/TD]
[TD]0,5 MOhm[/TD]
[/TR]
[TR]
[TD]red (1) & black (2)[/TD]
[TD]0.L[/TD]
[/TR]
[/TABLE]
[TABLE="border: 1, cellpadding: 1, width: 300"]
[TR]
[TD]black (1) & red (6)[/TD]...Leave a comment:
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You misunderstood, i measured the mosfets off the board, desoldered. What i meant with on/off is the mosfet itself:
"However, you should take note that when you put the positive of the DMM to the gate and the negative to the source of an NMOS, the MOSFET will turn on. You might mistakenly judge that the MOSFET is defective when you measure drain-to source resistance since the DMM will read 0 ohm. So, to avoid this scenario, ensure to discharge the charge on the gate".
The measurements of the 2 mosfets are like you specified.
ACOK is between...Leave a comment:
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0 ohm when mosfet is on, 0L when it is off.
I used this as a guide:
[url]https://electronicsbeliever.com/how-to-know-if-mosfet-is-defective/[/url]https://0 ohm when mosfet is on, 0L ...fective/[/url]Leave a comment:
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With resistance mode and the mosfets desoldered:
1.PQ8901 - QM3056M6AC
------------------------
source (pin 1,2,3) to drain (pin 5,6,7,8) - 0 Ohm / 0.L
gate (pin 4) to source (pin 1,2,3) - 0.L
gate (pin 4) to drain (pin 5,6,7,8) - 0.L
2.PQ8902 - P0903BEA
-------------------------
source (pin 1,2,3) to drain (pin 5,6,7,8) - 0 Ohm / 0.L (and 0,5 Mohm if i reverse the probes for some reason )
gate (pin 4) to source (pin 1,2,3) - 0.L
gate (pin 4) to drain (pin 5,6,7,8) - 0.LβLeave a comment:
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There really is something funky going on ACOK line, when measuring resistance, it goes from 0,7kohm and just keeps rising slowly to over 1kohm. It sure doesn't do either/or with 0v and 3v.
When I measure ACOK, i put black to GND and positive to the test pad shown on picture.
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3574124}[/ATTACH]β
How do i check if PQ8905A for proper functioning? according to the boardview it's this: [url]https:/...Leave a comment:
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It really was a pain to solder i have resoldered it (i'm confident it's good enough), yet the same things are happening.
The two DC in mosfets let the 19v as soon as i plug in the charger, so they should be good (but ill measure when i get home). It's just that the laptop is still unresponsive.
Then i measure ACOK - charging and power led come on and the laptop starts.
ACDET with power - 2,6 V
ACOK with power - 1,3 V
Looking at the BQ datasheet, I'm guessing that by measuring it with my multimeter, i am pulling ACOK high ? (don't know...Leave a comment:
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Hello again. I have replaced the BQ chip and now i have 19v passing the input mosfetsπ
However, when I replaced the IC, the laptop still wouldn't start. Then I started poking around the IC with the multimeter to check some values, and found a problem and solution combo ^^.
If i measure the voltage of pin 5 - PC_CHG_ACOK_10 (measuring on test pad that's right next to it), while the laptop is plugged in, it magically boots and charges. If i remove the probes, the laptop stays on, but stops charging. If I dont do this, the laptop does not respond to the power button.
...Leave a comment:
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I've ordered a new BQ IC. I also measured the voltage to pin 28 with the BQ removed and I get the 19V. Still curious why I'm getting 3.3v on my 19v rail... But we'll see.Leave a comment:
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Connected it to adapter. The replacement resistor actually died too π (went to something like 280ohm+). I have another identical one, but i'll wait for further advice now.Leave a comment:
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So I have desoldered the resistor and found that it really is faulty (shows 1,6 kOhm).
I measured the two pads :
pad 1 : ~10,5 kOhm
pad 2: ~280 ohm.
I also managed to find an identical, working resistor on another board and it is now soldered.
I'm guessing that this isn't the root cause? Resistor don't fail just like that?...Leave a comment:
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Although the boardview says 10ohm, doesnt the 100 marking on the resistor mean 100ohm? or am i missing something? To add: i havent replaced anything or worked on the board .
I do have a microscope, replacing wont be a problem. just got to find a replacement resistor on another board.
Thanks for the helpLeave a comment:
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Results are ... dodgy
[URL=filedata/fetch?id=3561212&d=1738339110][ATTACH=JSON]{"alt":"Click image for larger version Name:\tzoom_x512.jpg Views:\t0 Size:\t634.8 KB ID:\t3561212","data-align":"none","data-attachmentid":"3561212","data-size":"thumb"}[/ATTACH][/URL]
I'll try to remove it and remeasure everything next.Results are ... dodgy
[URL=filedata/fetch?id=3561212&d=1738339110][ATTACH=JSON]{"alt":"Click image for larger version Name:\tzoom_x512.jpg...Leave a comment:
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I'm assuming the resistor must be desoldered for checking right?
I'm also wondering where the hell is that 3,3v coming from
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