Hey All. I have the forementioned laptop that has no signs of life when plugged in. No charge indicator, no power lights, very dead. I got the main board out. I checked power going to the 9 pins on the board where the power jack connects. The first 4 pins read 19.4~ V, the 5th pin has nothing which makes sense since it's unused, the other 4 pins are grounded. I was trying to find a schematic to see if that's what it should be, but couldn't find anything. I also unplugged everything else from the board to try eliminating any additional shorting points. Does anyone have any suggestions on where to proceed next?
-
-
It seems like the power jack on your laptop may be faulty. Pin 1 - SLEEVE TERMINAL, Pin 2 - SHUNT TERMINAL and Pin 3 - TIP TERMINAL 2. The first 4 pins on your board read 19.4~ V, the 5th pin is empty and the remaining 4 pins are connected land. It's possible that the SHUNT terminal is not working correctly and this could be causing the problem. -
Since you have 19V on dc jack,check whether it reaches the CLR after 2 dc-in fets.Comment
-
Yes. Post clear pics of the top and bottom side of the logic board where the power enters the board. You should see (usually) 2 x mosfets. These are the tiny 8 pin devices with 4 pins on each side. They act like solid state relays. On 8 pin packaged devices, pins 1-2-3 are the source pins. Pin #4 is the gate. Pins 5-6-7-8 are the drain pins.
The part has a polarity so search for pin #1 which will often be identified with a dimple (dot) on the top side.
search for a datasheet to understand the pin out of the device.
we are after the voltage to ground on the source pin; gate pin; drain pins. Repeat for the 2nd mosfet. Measure carefully.
post all measurements.
these mosfets will be driven by a charger ic. We want a clear picture of the charger ic.
how this all works is very well documented by piernov in the above sticky. It is a must read.
Comment
-
So I found a similar thread for the board I have. They included a boardview of the 2.0 board, whereas I have the 2.1 This is where things get a bit complicated. The layout is a bit different than mine. In the boardview picture I verified voltage / ground and the A/D_DOCK_IN voltage on the PL600x chips . The A/D_DOCK_IN leads to other chips that don't match my board. I included a picture of my charging area the best I could. There's a lot of residue from the adhesive. If I had to assume, the 2 black chips near the 2R2s are the MOSFETS.
I wasn't sure what I was looking for on the profile.
Thread - https://www.badcaps.net/forum/troubl...-boardview-plzAttached FilesComment
-
-
See attached.
Remove all power. Meter in resistance mode.
Measure the resistance across each of these mosfets as follows:
source (1-2-3) & drain (5-6-7-8) ; these pins will be shorted on the board so pick anyone
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)
Post each measurement for each mosfet. Likely one of the mosfets is defective / leaking. You are testing the mosfets PQ8900 and PQ8901 from the schematic.Comment
-
source (1-2-3) & drain (5-6-7-8) - 163K Ohms on both mosfets
source (1-2-3) & gate (4) - 4.2 - 4.3M ohms on both mosfets across all 3 source pins and the gate
gate (4) & drain (5-6-7-8) - 1M ohms on the lower mosfet on each drain pin 1.1M Ohms on the other on each pin.Comment
-
This measurement is considered to be low for a mosfet. Suggest to flux and carefully remove one of the mosfets. Pick either one to get started. Then allow it too cool down and measure the removed mosfet again when it is on your work table. If the resistance remains to be low for the above source / drain measurements, it should be replaced. Continue to test the next mosfet for the same issue.source (1-2-3) & drain (5-6-7-8) - 163K Ohms on both mosfets
reference:
How to Know if MOSFET is Defective | ElectronicsBelieverComment
-
Hi all,
TL;DR - this laptop is driving me nuts with the oddball power-related behaviors. Appreciate any insight you can provide!
I'm experiencing a power issue on an Asus Probook P5440UF-XB74. Although I've worked with electronics and computers for decades, this is my first attempt at getting into motherboard-level component troubleshooting. Any help the community can provide is greatly appreciated!
A few weeks ago I was using the laptop (on battery power) for a Zoom meeting. The battery was running very low (long meeting) but I wasn't worried about... -
Hi all!
I'm trying to troubleshoot a Microsoft Surface Pro (5th gen) model 1796 that won't power on. Motherboard model is M1007506-015. My priority is retrieving data, but the SSD is integrated so it looks like if I can't repair it it'll need to go to a data recovery company. I've done a little basic board repair before, but nothing this advanced until now. So please forgive my ignorance in advance. 😅
I found the boardview for this laptop in the forums here, and am able to open it on my PC with FlexBV.
https://www.badcaps.net/forum/troubl...-hardware-devi... -
Hello, I have an issue with the motherboard. Specifically, it doesn't power on, more precisely, the POST initialization doesn't occur.
Let me start from the beginning, the motherboard suddenly stopped working one day. There are no beep signals from the speaker, and the debug LEDs are not lighting up. After inspecting it under a microscope and using thermal imaging, I didn't find anything that could be damaged.
After that, I began voltage measurements, in which I noticed the absence of VDDQ, VDDP, VTT, and VPP lines. Later, I checked if there is an EN state on these lines,... -
When I reflash again the bios of hoaca388 the unit powers on and the unit lives!!! Hooray!! All voltage in the coil 3.3v, 5v and 6.7v indicate charging are all present. including the cpu voltage , EEPROM and GPU voltage the unit is now alive, normal screen booting to windows and log in screen until I power it off. Then the unit never goes on even when pressing the power button in the keyboard.. Voltage reading 19v main , 3.3v VCC in IT8225E-128 and EEPROM VCC 0 volt and the charging voltage 0 volt.
Try to trace the power switch button goin to the power switch IC PU8803 (APL3533AQBI-TRG)... -
Hi all!
I've got an Asus FX517ZC on the bench at the moment and I just can't figure out what's going on with it.
Here are its various numbers and identifiers:
Model short: FX517Z
Model long: FX517ZC-HN114W
SN: NANRCX01S57842E
CN: 3SDB 12M
MFD: 2022-10
Motherboard model: DA0NJLMBAE0 REV E
Symptoms:
The laptop's charge light comes on, but when the power on button is pressed nothing happens. No fan spin, no caps lock, no screen or keyboard backlight, nothing.
History so far:
The...
Comment