Repair Help Lenovo IdealPad 5 15IIL05 power supply problem

[geoffrey5239]

Laptop Brand

Lenovo

Mobo Part No

NM-C681 GS557

Laptop Model No

IdeaPad 5 15IIL05

The schematic for this laptop includes a block diagram that shows the origin of the 3v 5v 0.6v 1.8v and 1.35v lines. These are shown as being provided by four Richtek chips. However these chips do not appear anywhere else in the schematics or boardviews. The problem with my laptop is a missing 1.8valw line which is shown on the block diagram as being provided by a Richtek LV5116A. I suspect that these Richtek items are within UE4501 (a IT8227VG chip) for which there is no on line documentation. Can anyone confirm this suspicion? Incidentally I have tried to reflow this BGA but this has not helped.

 

[Kalish]

The schematic for this laptop includes a block diagram that shows the origin of the 3v 5v 0.6v 1.8v and 1.35v lines. These are shown as being provided by four Richtek chips. However these chips do not appear anywhere else in the schematics or boardviews. The problem with my laptop is a missing 1.8valw line which is shown on the block diagram as being provided by a Richtek LV5116A. I suspect that these Richtek items are within UE4501 (a IT8227VG chip) for which there is no on line documentation. Can anyone confirm this suspicion? Incidentally I have tried to reflow this BGA but this has not helped.

yes. There is no IC. I am looking at the schematic.