I need helo on this lenovo b470 core i5 nvidia laptop, the problem is turns on only if battery only plugged in but if both battery and charger plugged in cannot turn on and also if charger only plugged in cannot turn on also. anyone can help on this please
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Re: lenovo b470 turns on only on battery
Send schematic and voltage details of charging ic pins -
Re: lenovo b470 turns on only on battery
i cannot find a schematic on this model, but i made a measurement with charger only plugged in on the ic BQ24745 base on datasheet pin3 VREF=2.5V pin2 ACIN=19v pin13 ACOK =3.3v but pin21 LGATE = 0vComment
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Re: lenovo b470 turns on only on battery
write the name of the motherboard for the right schematicComment
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Re: lenovo b470 turns on only on battery
on the main board i cannot find the markings of the board id but on the other board which connected to usb it has mark 48.4kz02.021. I have attached the photoAttached FilesComment
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Re: lenovo b470 turns on only on battery
I Have the schematic uploaded under Schematic-Forum search after B470
Put only AC adapter and then messure at Pu4001 voltageComment
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Re: lenovo b470 turns on only on battery
ok thanks as post#3 ive mentioned above some readings on pu4001 pinsComment
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Re: lenovo b470 turns on only on battery
@mielta sorry for the late response. here is the pu4001 all pins with charger only plugged in measurement
pin1=0v
pin2=2.6v
pin3=3.3v
pin4=0v
pin5=0v
pin6=0v
pin7=0v
pin8=0v
pin9=3.3v
pin10=3.3v
pin11=3.3v
pin12=0v
pin13=3.3v
pin14=0v
pin15=0v
pin16=0v
pin17=0v
pin18=0v
pin19=0v
pin20=0v
pin21=0v
pin22=19v
pin23=0v
pin24=0v
pin25=0v
pin26=3.3v
pin27=0v
pin28=19vComment
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Re: lenovo b470 turns on only on battery
anyone can help this pleaseComment
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Re: lenovo b470 turns on only on battery
Send clear picture near charging i.c side (bq24745)
and dcin connector side
please remove the cable from dc jackLast edited by qayyum786; 05-20-2020, 02:43 PM.Comment
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Re: lenovo b470 turns on only on battery
Upload clear image from marked area
parts number not so clearAttached FilesLast edited by qayyum786; 05-20-2020, 02:55 PM.Comment
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Re: lenovo b470 turns on only on battery
@qayyum786 here it is the picAttached FilesComment
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Re: lenovo b470 turns on only on battery
Connect battery and chatger both
than check voltages On BQ24745Comment
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Re: lenovo b470 turns on only on battery
anyone can help on this pleaseComment
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Re: lenovo b470 turns on only on battery
here is the measurement both battery and charger plugged in
pin1=0v
pin2=2.6v
pin3=3.3v
pin4=0v
pin5=0v
pin6=0v
pin7=0v
pin8=0v
pin9=3.2v
pin10=3.2v
pin11=3.3v
pin12=0v
pin13=3.3v
pin14=0v
pin15=11.08v
pin16=11v
pin17=11v
pin18=11v
pin19=0v
pin20=2.2v
pin21=6v
pin22=18.6v
pin23=12v
pin24=15.6v
pin25=18.6v
pin26=3.3v
pin27=19v
pin28=19vComment
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Re: lenovo b470 turns on only on battery
Did yiu replace the bq ic ?Comment
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Re: lenovo b470 turns on only on battery
REMOVE PQ4002 and check for voltage
On pin NO:- 7 = ?Comment
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Re: lenovo b470 turns on only on battery
i did not replaced the ic i just reflowed the chipComment
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Re: lenovo b470 turns on only on battery
Follow #18 & replyComment
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I got a Lenovo Thinkcentre MT-3218 that when I plug the power cord, the computer turns on. The power button seems to work just fine. When I press it the computer turns off, and when I press it again, it comes back on. But when I unplug the power, and plug it back again, it turns the computer on... does anyone have an idea what might be causing this strange behavior. Could this be the power supply or a bad contact on the power button?
thanks
PS: everything else on the computer works fine -
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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