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== Guides == | |||
{{List Guides}} | |||
== Device pictures == | |||
==Device pictures== | |||
<gallery showthumbnails="1"> | <gallery showthumbnails="1"> | ||
File:Example device pictures.jpg | File:Example device pictures.jpg | ||
</gallery> | </gallery> | ||
==PCB pictures== | == PCB pictures == | ||
<gallery showthumbnails="1"> | <gallery showthumbnails="1"> | ||
File:Example pcb pictures.jpg | File:Example pcb pictures.jpg | ||
</gallery> | </gallery> | ||
==Reference measurements (also schematics if available)== | == Reference measurements (also schematics if available) == | ||
<gallery showthumbnails="1"> | <gallery showthumbnails="1"> | ||
File:Example measurement pictures.jpg | File:Example measurement pictures.jpg | ||
</gallery> | </gallery> | ||
==External Sources== | == More Information/External Sources == | ||
=== Potential pitfalls === | |||
== 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 immediately 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. | * 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 immediately 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. | * 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. | * 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. | ||
Latest revision as of 20:14, 14 January 2024
| 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
Guides
Explanatory Guides
Repair Guides
Device pictures
PCB pictures
Reference measurements (also schematics if available)
More Information/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 immediately 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.