(Created page with "{{stub}} {{Device page }} ==Device pictures== <gallery showthumbnails="1"> File:Example device pictures.jpg </gallery> ==PCB pictures== <gallery showthumbnails="1"> File:Example pcb pictures.jpg </gallery> ==Reference measurements (also schematics if available)== <gallery showthumbnails="1"> File:Example measurement pictures.jpg </gallery> ==External Sources== == Potential pitfalls == The motherboard will not turn on without the I/O SubCard connected. Actually it wi...") |
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{{Device page | {{Device page | ||
|Manufacturer=Lenovo | |||
|Has code name=W541 | |||
|Device type=Laptop | |||
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==Device pictures== | ==Device pictures== | ||
Revision as of 19:50, 25 December 2023
| Thinkpad W541 | |
|---|---|
| Manufacturer | Lenovo |
| Code name | W541 |
| Release date | |
| Device type | Laptop |
This article is a stub. You can help Repair Wiki grow by expanding it
Device pictures
PCB pictures
Reference measurements (also schematics if available)
External Sources
Potential pitfalls
The motherboard will not turn on without the I/O SubCard connected. Actually it will turn on and then immediately assert -PWRSHUTDOWN, which will cause the first mosfet (Q9) to go off. This is most likely because the subcard has a power switch or regulator on it that is turned on by the VCC5MUBAY_DRV signal, and then the EC expects VCC5MUBAY to go high, and when it doesn't see it go high, it assumes something is wrong and turns off. Temporarily shorting TP28(VCC5M_IO_PWR-) to TP29(VCC5MUBAY) allows the motherboard to turn on even without the I/O SubCard. When flashing the BIOS using a SOIC clip, the programmer device needs to strongly drive the HOLD# pin high. A 5.6kOhm pull-up was not strong enough. A dead short worked successfully. The 4MiB and 8MiB BIOS flash chips share MISO/MOSI/SCK lines. When programming them using a SOIC clip, it has been observed that often the CS# line of the other chip has a low enough voltage and that the other chip could be considered selected as well. This did not cause a reading/programming failure so far, but if any issues are observed in the future, then it may be worth forcing the CS# line of the other chip high.