Lenovo t440 notebook battery large current maintenance

Lenovo t440 notebook battery large current maintenance

[machine model] Lenovo t440 notebook

[main board No.] nm-a131

[fault phenomenon] laptop plug-in battery large current

[maintenance process]

Received a Lenovo t440 machine, a little old, board model: nm-a131, plug in the battery, power on large current,auto power off pool, normal operation into the system.

Take down the machine, take it down, visually check that the upper tube of the standby pq16 has been replaced, and the standby chip has been passively passed through this, regardless of the normal opening of the machine.

Lenovo t440 notebook plug-in battery large current circuit maintenance Figure 1
Find the battery chip pU7 bq24760, and test large current on the bare battery board. Your hand just touches a place, which is very hot. Look at MOSFET, which is a common S-tube of q85, pq13 and pq34.

Lenovo t440 notebook plug in battery large current circuit maintenance Figure 2

Lenovo t440 notebook plug-in battery large current circuit maintenance Figure 3

It’s a bit like p-tube. You can’t replace it with p-tube. You need to find S-tube and replace it with Lenovo think motherboard.Plug in the battery, it won’t Short circuit, but if you don’t plug in the battery, it will go out if you don’t plug in the battery. What’s more, it’s still the same to replace the charging chip. After tracing the source of q85, we found that the charging chip 4 pin acdet, the back position of the motherboard pq167 MOSFET[don’t know what MOSFET]schematic looks like againdiodeIt’s like that againtriodeIs it a composite triode?This MOSFET can’t see clearly if you don’t look carefully. It’s too small.

Lenovo t440 notebook plug-in battery large current circuit maintenance Figure 4

This MOSFET is still replaced from think Parts motherboard. Plug in the battery and power on the large current, or start the machine without auto power off. It can be charged, troubleshooting, and maintenance.

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