Excellent, thanks for the schematic.
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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 guys, my motherboard will not start no matter what
when connected to ac power, the battery does get charge, led indicator glows red when discharged and turns white as it is fully charged.
but rest nothing happens no sign of life.
this laptop has one preexisting usbc power issue - so i use DCIN jack for charging my laptop.
with this issue my laptop was unable to power ON only sometimes i just had to wait some time.
but now nothing happens no matter how much i wait/ charge/ press and hold power button.
i have no knowledge of motherboards ....10-20-2024, 02:48 PM -
For Badcaps Readers, Please note that I am hopefully going to present this same message to Lenovo to see if they have any insight to the matter as well and figured to share the entirety here for clarification. The System is out of warranty as it is but does have the option to have it extended.
Model Information: T14 Gen 2 (Type 20XK, 20XL) Laptop (ThinkPad) - Type 20XK - Model 20XK0069US
Board: T14 Gen 2 (Type 20XK, 20XL) - Type 20XK.
System Hardware:
Processor: AMD Ryzen 7 PRO 5850U
Memory: 1x 16GB DDR4 3200 (Soldered on Board); 1x Crucial 32GB DDR4...09-08-2025, 10:46 PM -
I am seeking guidance on an Acer Spin 1 SP111-33 that does not turn on when pressing the power button.
Below are the observations and troubleshooting steps I have taken so far: Observations and Tests:- Verified that all critical voltages are present:
- 3.3V and 5V are always present if DC is plugged.
- 1.8V on the BIOS chip is present.
- Checked the power button functionality:
- When pressed, the voltage drops to 0V, indicating the button is functional.
- Inspected the flex cable connecting the USB, audio, and power button to JUB1:
- Confirmed connectivity is intact, ruling out issues
11-26-2024, 12:39 AM - Verified that all critical voltages are present:
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Dell laptop (E7440, uses the notorious CD3301B power controller + MEC5075 EC + BQ24715 charger IC)
Symptoms:- Laptop works normally on a pre-charged battery.
- Battery does not charge when adapter is connected.
- Without battery:
- Laptop powers on from DC adapter, passes CPU/RAM init checks, then cuts DC power abruptly.(seems to shutdown one of the mosfets in the charger path). Then the loop continues indefinitely
- Speakers “pop” when power cut occurs indicating harsh sutdown.
- If RAM is removed, the system shows RAM missing blink error code indefinitely without cutting DC power
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