Re: lenovo b470 turns on only on battery
pr4001=202.8kohms
pr4001=202.8kohms
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Re: lenovo b470 turns on only on battery
here is the photo i start measuring on the upper as pin 1Attached FilesComment
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Re: lenovo b470 turns on only on battery
you are right as i checked on the schematic pin 6 has 19v and pin5 has 3.3v pin 4 is connected to the ground but pin 1-3 is beeping to the ground could it be shorted?Comment
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Re: lenovo b470 turns on only on battery
Change pq4001
or remove it and just jumper from pin 4 to pin 3Comment
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Re: lenovo b470 turns on only on battery
Remove pq4001 and
jumper as i have shown in imageAttached FilesComment
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Re: lenovo b470 turns on only on battery
You get confused during counting the pin of pq4001
now
just let me know the voktage of pu4001 voltages of source - gate - drain
pin 1,2,3 = ?
Pin 4 = ?
Pin 5,6,7,8 = ?
Please don't make mistakes during measuring the voltages on pinComment
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Re: lenovo b470 turns on only on battery
Hi
check PR4006 voltage before and after resistor
its connect direct to your +Ad and your pin2 of bqComment
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Re: lenovo b470 turns on only on battery
ACIN is 2.6 v
Please Check #8
That means PIN 2 ACIN volt is perfect for BQ24745
Thanks @MOHAMMAD for your supportLast edited by qayyum786; 05-21-2020, 11:15 AM.Comment
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Re: lenovo b470 turns on only on battery
@qayyum786 pu4001 here it is ive measured again
pin 1,2,3 = 19v
Pin 4 = 6.58v
Pin 5,6,7,8 =19vComment
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Re: lenovo b470 turns on only on battery
That means PQ4001 & PU4001 both are ok
Remove PU4002 and check with adapter only
Dose laptop power on with adapter after removing PU4002Comment
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Re: lenovo b470 turns on only on battery
removed PU4002 plugged in charger only laptop cannot power onComment
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Re: lenovo b470 turns on only on battery
I noticed alson that no voltages on DRAIN of pu4002 and on pr4005 it has only 10kohms on the schematic supposed to have 470kComment
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Re: lenovo b470 turns on only on battery
When you masure VOLT ON DRAIN before removing PU4002
Or masure it after removing PU4002Comment
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Re: lenovo b470 turns on only on battery
Change
pr4005
pu4002
pu4004
pu4005Comment
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Re: lenovo b470 turns on only on battery
when i measured the pu4002 with in the board and removing its the same measurement no drain voltagesComment
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Re: lenovo b470 turns on only on battery
Yes afcors if you check voltages WITHOUT BATTERY
& iCHARGER PLUG IN you will not get any voltages on DRAIN
DRAIN is connected to the BATTERY SIDE
Do you know how to test MOSFET FOR SHORT
If yes than REMOVE CHARGER & BATTERY BOTH and masure
pu4002
pu4004
pu4005
I guess 1 of them is shortedComment
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Re: lenovo b470 turns on only on battery
check on diode mode on pu4004 black probe on source and red on drain it has 0.200v and on pu4005 it has 0.500v pu4002 0.465vComment
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Re: lenovo b470 turns on only on battery
with charger plugged in pu4004 drain have voltage but source no voltage PU4005 both drain and source no voltageComment
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Re: lenovo b470 turns on only on battery
All 3 mosfet check out side of motherboard
if all 3 fet is ok than bq ic is victimComment
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Re: lenovo b470 turns on only on battery
you mean i pulled out the 3fets and check outside motherboard?Comment
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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:
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