Lenovo B50 LA-B091P ... BQ24737 ==> VCC 19V , ACDET 2.59V, SRN 2.2V, REGN 6V, ALL mosfets are OK and Power Rail not Shorted and ACOK wont Pull Low !!! So second Power mosfet will not be active ... is there another signal responsible of activating ACOK# in this situation ?? it must pull down to ground so the signal PACIN go HIGH
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Hi there,
I have a DK10FG-6050A2491301-MB-A03 motherboard with missing ACOK voltage. Here are the basic voltages of BQ24725A. The motherboard is dead with no signs of life.
ACN : 19.35V
ACP : 19.36V
ACDET : 2.7V
REGN : 5.916V
VCC : 19.36V
Diode mode to ground reading on ACOK rail is 0.450V on pin 1 of R6013 and 0.230V at pin 2. Replaced BQ24725A a couple of times. Still no luck.
The problem was that I was not having 3.3V/5V from the TPS51225 regulator. So I tracked down to the BQ24725A which was missing the ACOK voltage... -
Hello everyone, I need your help. I'm having issues with a Lenovo motherboard. When I plug in the charger, there's no current consumption. However, the laptop works if I bypass the charger IC by applying 20V directly to the main resistor. I checked the voltages at the charger IC and found that ACOK (AC OK signal) is missing, and ACDRV (AC Drive) isn't sending voltage to the gates. I've searched for shorts but found none. I replaced the charger IC three times, but ACOK remains around 0.24V–0.35V. The MOSFETs test fine. If anyone has encountered this issue, I'd appreciate your advice. -
Machine won't power on, no power led, no fan spin, completely dead.
Checked PQ5400 - AONS32314 and pins 5,6,7,8 are 20v (AC adaptor voltage) but pins 1, 2, 3, 4 are 0v.
Following Gate Pin 4 to PU5400 - BQ24780SRUYR.
VCC 20v
ACDET 2.8v
ACDRV 0v (goes to pin 4 gate of AONS32314).
ACOK 0v
REGN 6v
According to datasheet, conditions are correct for ACOK to be high but it is not.
Tracing ACOK it's connected to ACIN which is connected to a pin GPB0 of IT8227 but also shown as connected to +3VL via a 100k resistor... -
Laptop Model: Acer Aspire 3 A314
Motherboard Model: DA0Z8EMB8C0 - Model: Z8E
Charging IC: BQ24780 which I have repalced.
Issue Description:
I'm experiencing an issue with the charging system on this laptop. The BQ24780 charging IC is not working as expected. The main problems are:- ACDET is missing (0V):, Reading 0V on the ACDET pin.
- ACOK is not present (0V): Is missing as well.
- No SMBus signals (SDA and SCL are missing): The SDA and SCL signals for SMBus communication are not present. There is no clock (SCL) or data (SDA) activity on these lines.
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Problem
This is an LG edge LED lit LCD Display. The LEDs are on the bottom edge of the display. There are 2 bars (left and right) Each bar has many LEDs and a 6 pin connector. Each pin drive several LEDs thus is the highest current flow / heat junction. The weak lead free solder gradually fails with thermal expansion/contraction cycling and increases resistance. PSU will compensate up to a point, then when the current is too high, PSU just shut down the backlight causing a dark display. I have even seen one which the connector just fell off as solder points became completely detached....
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