Lenovo T470 not charging

[mohamed mm]

Hello everyone,

The client brought me a laptop Lenovo T470 and it's not charging, the client said the battery is good and this suddenly happened to him, and reading from Ic charging it's like this:

(BQ25700RSNR_QFN32_4X4) ic name.

1: VCN= 20V
2: VCP= 20V
3: VBUS= 20V
7: VDDA= 6V
4: CHGR_OK= 3.3V
21: BATDRV#= 3.3V
22: VSYS= 9.2V

3 pins in the battery connector have 3.3v, and when I connect the battery one goes 2.3v and the other two pins stay in 3.3v.

what else do I have to check? ask me anything and I will replay as soon as possible.

there is a pic of battery charger.
Thank you.

[mon2]

Re: Lenovo T470 not charging

Connect the battery.

Measure the voltage to ground of:

SRN
SRP

[mohamed mm]

Re: Lenovo T470 not charging

with battery:
SRN= 9.2V

SRP= 9.2V

without battery:
SRN = 9.2V

SRP= 9.2v

Thank you for respond

[Stevedb]

Re: Lenovo T470 not charging

How much voltage do you have on ac drive.

[mohamed mm]

Re: Lenovo T470 not charging

do you mean ACN?

ACN= 20v

[Stevedb]

Re: Lenovo T470 not charging

Sorry i was mistaken i thought it was bq24780s. The charging ic. i was mistaken with another treath.

[mon2]

Re: Lenovo T470 not charging

Link the full schematic when you can. Braincells are being wasted today on retooling our dreaded smt line for a new part.

[mohamed mm]

Re: Lenovo T470 not charging

this is the schematic,

[Vesko356]

Re: Lenovo T470 not charging

this is the schematic,

Please link to topic in the Schematic subsection rather than uploading schematics in your post here!
I'm tired of editing posts in the section. Finally, I will start deleting all replies with attached schematics.
Please edit your post!

.

[mohamed mm]

Re: Lenovo T470 not charging

I was not aware of the existence of such a violation and I will not do it again, but I cannot delete or modify the response because the modification option has disappeared.

Lenovo T740 schematic link.

https://www.badcaps.net/forum/showthread.php?t=78951

[mon2]

Re: Lenovo T470 not charging

Confirm the voltage to ground of each pin on connector PJ2. Connect your battery while checking.

Confirm the voltage to ground on each side of fuse PF3.

[mohamed mm]

Re: Lenovo T470 not charging

Pj2 & pj3

without battery,

1pin= 0.21v

2pin= 0.21v

3pin= 3.3v

4pin = 3.3v

5pin= 3.3v

6pin= 0.0

7pin= 0.0

fuse= 0.21v

with battery:
1pin= 0.0v

2pin=0.0v

3pin= 3.3v

4pin= 3.3v

5pin= 2.06v

6pin= 0.0

7pin= 0.0

fuse= 0.0

[mon2]

Re: Lenovo T470 not charging

Remove all power. Remove the battery.

Meter in resistance mode.

Check the resistance of the same fuse using the meter probes across the fuse.

[Vesko356]

Re: Lenovo T470 not charging

I was not aware of the existence of such a violation and I will not do it again, but I cannot delete or modify the response because the modification option has disappeared.

Lenovo T740 schematic link.

https://www.badcaps.net/forum/showthread.php?t=78951

The name of the subsection speak for itself, all the schematics must be placed there, not all over the forum. It's interesting how you would easily find a schematic in a forum without knowing exactly which section to look in for it?
Not to mention it is very easy to assume that if the same schematic is uploaded several times in a hundreds of created threads, it will overflow the server free space. We still have critical difficulties with this problem - there is a sticky thread regarding this issue:
"IMPORTANT ANNOUNCEMENT. Possible closure of Bios Requests"
https://www.badcaps.net/forum/showthread.php?t=116453

.

[mohamed mm]

Re: Lenovo T470 not charging

FUSES with probes on both sides:

fp3= 000

fp4= 000

FUSES with black probe on ground and red on one side of the fuse:

fp3= 1.9 mega ohm

fp4= 1.9 mega ohm

[eliemgh]

hello . i have a problem on t470 batteries, the voltage on battery cellule is ok (total 12 volts) but on board no voltage . any one can help me