This article is a stub. You can help Repair Wiki grow by expanding it
| Thinkpad W541 | |
|---|---|
| Manufacturer | [[:Category: s|]] |
| Code name | |
| Release date | |
| Device type | |
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.