Hello!
I've this mb that won't boot, already tried BIOS flashback.
I suspect a faulty PU1 (RT8065ZQW)
I have this readings on PU1 pins:
- 1 = 5.19V
- 2 = 5.18V
- 3 = 3.42V
- 4 = 5.19V
- 5 = 0.9V
- 6 = 0.9V
- 7 = 0.67V
- 8 = 3.42V...
DrFalken
Senior Member
Last Activity: 06-11-2026, 06:35 AM
Joined: 05-28-2008
Location:
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ASUS Z97-PRO (WiFi-ac) Rev. 1.01 - error 00 - 1 second boot loop
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Lenovo Thinkpad T14 Gen 1 - dead
Hello guys,
a customer brought this laptop completely dead.
M/B: GT4A0/GT5A1/GP4A0/GP5A1/GT4A2 NM-C931 Rev 1.0
The original power supply had the 3 wires of the cable cut because the customer said that it often did not charge so, thinking it was a bad contact of the cable, he tried to repair by himself
He said the laptop stayed on until the battery was completely drained: then brought a new PSU (I guess on amazon...) but the laptop no longer turns on...
I've found visually broken U6302 (see attached pic) and I'm trying to remove the resin: meantime I've... -
Checked again, confirmed readings.
Should I put back PRB9 and check mosfet again ?
Or maybe BQ24738 is not fully compatible with BQ24735 ?... -
Readings with PRB9 removed.
BQ24735 (actually BQ24738):
pin 1 ACN = 0.315V
pin 2 ACP= 0.921V
pin 3 CMSRC = 0.89V
pin 4 ACDRV = 0.89V
pin 5 ACOK = 0
pin 6 ACDET = 2.91V
pin 7 IOUT = 0
pin 8 SDA = 0
pin 9 SCL = 0
pin 10 ILIM = 0
pin 11 BATDRV = 1.7V
pin 12 SRN = 1.01V
pin 13 SRP = 1.01V
pin 14 GND = 0
pin 15 LODRV = 0
pin 16 REGN = 6.01V
pin 17 BTST = 5.79V
pin 18 HIDRV = 1.01V
pin 19 PHASE = 1.01V
pin 20 VCC = 19.47V
PRB6 = 10.1 O...Leave a comment:
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Resistor removed (PRB9).
ACDRV_CHG = 0.9V
Replaced also PQB12 & PQB13 with AON7752: same reading....Leave a comment:
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Replaced BQ24735 with BQ24738, now I read 1.28V @ACDRV_CHG_R
Update: replaced PQB11 but ACDRV_CHG_R drop again to 0
Last edited by DrFalken; 12-06-2025, 06:04 AM.Leave a comment:
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No, nothing of "protection for reverse input" is onboard......Leave a comment:
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You mean BQ24735 ?
Pin 1-2 = 0 (or very low...maybe because of PRB1)...Leave a comment:
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With and without PSU plugged:
ADP_SIGNAL to GND = 19.9 kOhm
(PSU always disconnected from power)...Leave a comment:
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Yes, HP 255 G7...Leave a comment:
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Checked ADP signal (center pin) directly at power connector of 2 different (one Sandberg and one Chicony brand, both working with other laptop) PSU:
- First PSU is 0.02V
- Second PSU is 0.10V
When I plug the connector, ADP_SIGNAL (pin 6 @PJP1) is 0.
ADP_SIGNAL to GND = 19.9 kOhm...Leave a comment:
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ACIN (@PRB15) = 168.6 kOhm
ADP_ID = 0
...
Leave a comment:
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Leave a comment:
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Confirmed, not shorted.
PQB11:
- source / drain = 3 MOhm
- source / gate = open
- gate / drain = 3.36 MOhm
PQB12:
- source / drain = 3.1 MOhm
- source / gate = open
- gate / drain = 3.7 MOhm
PQB13:
- source / drain = 1.4 MOhm
- source / gate = open
- gate / drain = 3 MOhm
...Leave a comment:
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HP 255 G9 dead
Hi guys,
yesterday a client brought this laptop completely dead.
I've found liquid spill on the motherboard's top.
Battery removed.
ACDRV_CHG_R missing on both PQB11 & PQB12.
BQ24735 readings:
- VCC: 19V
- ACDET: 2.91V
- REGN: 6V
- ACOK: 0
- SRP/SRN to GND: 1V floating
- PRB11: 0
What sould I check ?
Can I swap BQ24735 with BQ24738 ?
Thank you !... -
TVS removed and....all USB are back to work !
Actually I've found the audio codec (Realtek ALC887) extremely hot and not working.
I'll look for a donor board to replace all the TVS & codec chip and report back....Leave a comment:
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The data lines do not appear to be shorted (I checked all the TVS).
I checked the internal USB 2.0 ports (USB1112 and USB1314) and they work while the internal USB 3.0 (USB3_12) does not work.
Out of curiosity I checked the Ethernet port and it does not work (the LEDs remain off)
From the Linux terminal I saw that the USB 2.0, 3.0 and Ethernet controllers are correctly enumerated.
Could it be a partially faulty PCH?
Should I remove the TVS anyway and see if anything changes?...Leave a comment:
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ASUS B85M-E: USB and PS/2 not working
Hi!
I have an ASUS B85M-E with non-working USB and PS/2 ports.
GND and 5V are present.
I have tried other PCI and PCIe USB cards, but it still doesn't work.
I have reset the CMOS, updated the BIOS, but the problem is still the same.
What else should I check?
Half dead chipset ? -
Thank you for the reply.
I suspected the SOC was shorted because it gets really hot in the 5 seconds the board is on and also the resistance to GND on those 2 inductors is way too low.
Out of curiosity, I tried flashing the BIOS with another BIOS and the board doesn't turn on at all: if the BIOS is run by the CPU, why this behavior if it is dead/faulty ?...Leave a comment:
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Dell Inspiron 5593 shutdown after 5 seconds
Hello everyone!
Motherboard model: FDI55 LA-J081P
Today a customer delivered this laptop completely dead, with the original power supply shorting when plugged into the connector.
I found and replaced a shorted MOSFET (PQZ3).
Now the laptop turns on (fan runs fine but no video signal) and after 5 seconds it turns off.
BIOS has already been updated (both 64MB and 128MB IC)
+3VALW and +5VALW are still present.
+VCCIN = 1.8V stable (measured on PLZ1 at power up)
Abnormal readings:
PLZ1 to GND = 0 Ohm
PLZ2 to GND = 0 Ohm
...
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