Re: FH51M LA-J871P charging issues
Thank you @mon2 and @mcplslg123. PQB3 is indeed shorted as tested out of the board.
I clearly don't know enough about these types of charging circuits, I never realized the computer could still work even with a shorted mosfet in these HPB designs. I have learned a ton from you.
I ordered a CSD17573Q5B as that's what I could find quickly without ordering from China. Hopefully, it will work.
Thanks again!...
reparetech
Member
Last Activity: Yesterday, 10:34 AM
Joined: 03-15-2021
Location: Quebec City / Qc
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Re: FH51M LA-J871P charging issues
Thanks. The sticky is exactly what I read, I unfortunately missed the part about the gate voltage though.
PQB3:
S-D: 0.20 ohm
S-G: 2.08 Kohm
G-D: 2.90 Kohm
PQB4:
S-D: 0.280Mohm and growing (39.32 Kohm measured in reverse)
S-G: 2.09 Kohm
G-D: 0.260 Mohm
Removed PQB4, PQB3 short between source and drain is still present.
Thermal camera (before the mosfet was removed) showed no shorted caps anywhere, so I can safely assume PQB3...Leave a comment:
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Re: FH51M LA-J871P charging issues
Sorry, I must have had a finger on the probe, pin 1 actually measures 19.069V. With that measurement, iadp (pin 7) seems to make a lot more sense.
While battery and charger are plugged in:
PQB3:
Pin 1-3: 19.739V
Pin 4: 19.733V
Pin 5: 19.740V
PQB4:
Pin 1-3: 19.739V
Pin 4: 19.733V
Pin 5: 19.158V-19.161V
PRB3:
Pin 1-2: 19.158V-19.161V
Pin 3-4: 19.158V-19.161V
PRB3 fluctuates constantly
Is it safe to assume +19V_P2...Leave a comment:
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Re: FH51M LA-J871P charging issues
1: 18.960v
2: 19.157v
3: 19.729v
4: 19.727v
5: 3.295v (acok)
6: 2.593v (acdet)
7: 1.903v
8: 0v
9: 0v
10: 0v
11: 3.180v
12: 3.198v
13: 0v
14: 0v
15: 0.151v
16: 0.107v
17: 15.927v
18: 15.913v
19: 15.926v
20: 15.926v
21: 1.045v
22: 0v
23: 0v
24: 6.042v
25: 15.646v
26: 15.780v
27: 15.927v
28: 19.390v
ec_smb_da1: 3.190v
ec_smb_ck1: 3.201v
I don't...Last edited by reparetech; 11-08-2023, 07:01 PM.Leave a comment:
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Re: FH51M LA-J871P charging issues
1. Sorry, I posted the schematics to help people who would want to dianose the issue.
2. I have actually tried two batteries. Started with a non-original one and then ordered an original Acer battery. Same issue.
3. Pin 19: 15.938V, pin 20: 15.938V Also measured 20.1 ohms between pin 19 and 20.
Thank you very much for your help....Leave a comment:
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FH51M LA-J871P charging issues
Hi, I have this Acer Nitro FH51M LA-J871P that intially came in because it did not turn on at all.
Short detected on +19VB which turned out to be PC1105 shorting +19VB_1VALW. Capacitor removed and replaced.
Now, the computer turns on (on charger, and on battery), but it does not charge and the charging light flashes after about a minute.
What has been done:
- PUB1 has been replaced, didn't change anything.
- Changed battery, didn't work
- Changed charger, didn't work
- Updated BIOS (When it was updating, the charging light...Last edited by SMDFlea; 11-09-2023, 05:33 AM. -
Re: Lenovo NM-C421 partial RTCVCC short
Thank you very much, this is exactly why I asked on this forum, I never would have thought to check the other circuits related to the RTC.
Unfortunately, the short is still present, so I'll call this one dead.
Thanks again !...Leave a comment:
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Lenovo NM-C421 partial RTCVCC short
Hi, I seem to have a partial short on the VCC3SW circuit coming from RTCVCC.
[LIST][*]VCC3SW initially measures about 1.1V.
[*]RTCVCC to ground measures approximately 9 ohms, but it does seem to fluctuate as I have measured it at 2 ohms.
[*]There is no apparent water damage (or any other damage) on the board.
[*]Removing PD0001 disconnects RTCVCC from VCC3SW and VCC3SW is back to 3.3V.
[*]R1301 measures about 1M measured directly on board
[*]C1608 and C1609 have been removed.
[*]There is no CMOS battery connected.
[*]C2001 is a no stuff.... -
Re: Identifiying this component on a ASUS X512JA board
I love the guess, thank you very much. Unfortunately, as pin 1 is at +19V, it is not plausible per the specified absolute maximum ratings in the datasheet. Thank you again, it's much appreciated....Leave a comment:
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Identifiying this component on a ASUS X512JA board
Hi,
I have what a X512JA with no backlight. This is caused by the screen not getting any voltage on the backlight pins. This IC, which I believe is a load switch, is not taking the Vin and sending it to Vout. Vin in this instance, being the AC or Batt, and Vout being the rail going directly to the 4 backlight pins on the edp connector.
I believe the markings on the first line is W07T, second line 2176.
I would like more information on this IC, or a boardview if available (I have looked for this speicfic model and could not find it. I also looked... -
Re: New Members - please post your introductions here
Hi,
Hope everyone is well, I have been lurking on this forum for quite a while now, and it’s been of much help. I own a repair shop focused mostly on basic phone repairs, but I get laptops thst need some soldering once in a while. I’m hoping to be able to offer some help once in a while, and to possibly offer some schematics or boardviews that are only available via paid ressources, when possible.Leave a comment:
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