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==Guides== | ==Guides== | ||
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===Known Problems=== | ===Known Problems=== | ||
An old version of the bios present on some machines like the T480 is known for continuously writing to the EEPROM that controls the USB-C port. This will slowly damage the port eventually destroying it. The damage can be stopped by updating the bios but can't be reversed. This requires replacing and reprogramming the EEPROM. TODO: Write a repair guide on how to fix this problem. | An old version of the bios present on some machines like the T480 is known for continuously writing to the EEPROM that controls the USB-C port. This will slowly damage the port eventually destroying it. The damage can be stopped by updating the bios but can't be reversed. This requires replacing and reprogramming the EEPROM. TODO: Write a repair guide on how to fix this problem. | ||
===Notes=== | |||
* This laptop can still boot if the second phase of the VCCCPUCORE is missing (i.e. if the PU403 dual-mosfet chip is removed). It is not recommended to leave it unpopulated, but the information that it can boot like this is useful for debugging purposes. For example if you have a dead NCP302045 on VCCGFXCORE, and no NCP302045 chips in stock, then you can temporarily steal the NCP302045 from VCCCPUCORE's second phase for testing purposes, to see if it's even worth ordering a replacement part, or if the dead dual mosfet killed the GPU as well while it died. | |||
* If the laptop keeps powering off and on every second or so, with the screen never turning on, it may be because VCCGFXCORE doesn't turn on when it is commanded to. Memory initialization happens before VCCGFXCORE is turned on, so if you remove all memory you will get the no memory beep code, without the repeated power-off/power-ons. | |||
===Defects Observed=== | |||
Please consider contributing by expanding this list, or by incrementing the numbers in this list if you find the same defect. | |||
{| class="wikitable" | |||
! Defect !! Economically Repairable? || How many times observed? | |||
|- | |||
| Mosfet on the VCCGFXCORE power rail shorted to VSYS. This blew PL407 with visible scorch marks. Fixing this didn't help, so iGPU probably died from this || no || 1 | |||
|- | |||
| VCC1R0_SUS (PL701) shorted to ground, by PCH. Cracks observed in PCH underfill, but only noticable under microscope. || no || 1 | |||
|} | |||
Latest revision as of 07:53, 7 February 2024
| Thinkpad T480 | |
|---|---|
| Manufacturer | Lenovo |
| Code name | Windu-2, NM-B501 |
| Release date | |
| Device type | Laptop |
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More Information/External Sources
Known Problems
An old version of the bios present on some machines like the T480 is known for continuously writing to the EEPROM that controls the USB-C port. This will slowly damage the port eventually destroying it. The damage can be stopped by updating the bios but can't be reversed. This requires replacing and reprogramming the EEPROM. TODO: Write a repair guide on how to fix this problem.
Notes
- This laptop can still boot if the second phase of the VCCCPUCORE is missing (i.e. if the PU403 dual-mosfet chip is removed). It is not recommended to leave it unpopulated, but the information that it can boot like this is useful for debugging purposes. For example if you have a dead NCP302045 on VCCGFXCORE, and no NCP302045 chips in stock, then you can temporarily steal the NCP302045 from VCCCPUCORE's second phase for testing purposes, to see if it's even worth ordering a replacement part, or if the dead dual mosfet killed the GPU as well while it died.
- If the laptop keeps powering off and on every second or so, with the screen never turning on, it may be because VCCGFXCORE doesn't turn on when it is commanded to. Memory initialization happens before VCCGFXCORE is turned on, so if you remove all memory you will get the no memory beep code, without the repeated power-off/power-ons.
Defects Observed
Please consider contributing by expanding this list, or by incrementing the numbers in this list if you find the same defect.
| Defect | Economically Repairable? | How many times observed? |
|---|---|---|
| Mosfet on the VCCGFXCORE power rail shorted to VSYS. This blew PL407 with visible scorch marks. Fixing this didn't help, so iGPU probably died from this | no | 1 |
| VCC1R0_SUS (PL701) shorted to ground, by PCH. Cracks observed in PCH underfill, but only noticable under microscope. | no | 1 |