Hi, Working on a Lenovo X1 Carbon 1st Gen (Type 3444) Laptop. Came in for battery problems. Upon testing the battery, I noticed that one of the cells is bursted & has to be replaced. Ordered a Brand New battery. Now it works on battery but does not charge at all. I see in Windows 10 it shows the charging sign & AC power connected but stuck on 79%. I did a press-in switch reset at the botton of the laptop, but did not help. Checked the Voltage on the chip BQ24760RSBR, all seem to be fine. Battery voltages are ok 14.4v but on the battery coil L24, when AC is plugged in I only get 1.8V. Then I checked abnormal behavior on the battery connector. Data/clock both 3.3v. But on the M_TEMP pin (pin 6) there is 2.1v, where as this should be LOW (ZERO) when the battery & AC Power is connected. When I remove the battery terminal, Pin 6 is back to 3.3v. I check all the resistences, all are fine. This signal comes directly from I/O Chip U36. Is there a way I can disable this & battery temp rail to start battery charging again. I have uploaded the Schematic for review. Any tips/help will be greatly appreciated. Thanks in advance.
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My question pertains to understanding the control circuity inside a Dell PT434 type battery used in Dell E6400, E6410 and other Dell notebooks?
Does anyone have a circuit diagram for the inside of a Dell PT434 battery and/or a description of how the control lines work to control this battery?
My reason for asking is I have a battery which I cannot get to charge beyond 1% in a Dell E6410 or E6400.
The LED bar graph charge indicator on the battery shows one LED lighted when the info button is pressed.
I have tried multiple different Dell power adapters. My Dell... -
Lenovo Ideapad 320-15IKA
NM-B452
Hi guys. I've used the forum a lot but never asked questions before. I had a Lenovo come in that was shorted on the 20V rail. I fixed that and thought my job was done until I realized it wasn't charging the battery. Here is what I've checked so far
On the BQ24780SRUYR charging ic
VCC 20V
SMBUS lines
SDA 3.3V
SCL 3.3V
Current Sensing lines
ACP/ACN 2.3 ohms
SRP/SRN 21.2 ohms
REGEN line 6V
PHASE .84V with no battery installed(this may be normal)
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Hi all
We have in a HP ProBook 445 G8 laptop with AMD Ryzen 7 CPU. When power is connected the power LED light blinks 5 times then stops. Normally HP laptops will blink this LED 10 times as it does a self test when the AC adaptor is inserted. So there must be some sort of short somewhere.
The battery doesn't charge, and is erratic on the MM voltage. Bench PSU LED pulsates when the battery is connected also. So the fault must be on the charging circuit?
I have gone around the board with a MM and cant find anything
Windows shows the battery fine,... -
1. Some theory
1.1. Introduction
Almost every laptop has a charging circuit of some sort, that does a few things:- Manages switching between AC adapter and battery power
- Manages battery charging and generates power rail to charge battery
There are 2 different designs to handle switching between AC adapter and battery power and feeding the system:- Hybrid power boost (HPB) and traditional circuits without power boost (see Warning in HPB section)
- Narrow VDC (NVDC)
Texas instrument has a nice overview of these technologies with some more details at https:... -
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
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