This is a guide that I am writing for helping others to replace their MEC1503 EC chip if it breaks (or to get around an inconvenient prompt to the BIOS). This forum has been extremely helpful to me so I would like to contribute to help others. I will tell you right now that this task is very difficult to do. You MUST have experience and tools to do precision micro-soldering, BGA reballing, trace repair, and general laptop repair skills.
There are some specialty tools needed to do this task. The replacement MEC1503 chips can be acquired from Aliexpress. Do not buy the bare chips as these are often fake or unprogrammed. I bought a few "whole board stripper plate" from the seller "Shenzhen Xin Xin Electronics Co LTD Store". These are motherboards that have the CPU, memory, wifi, and usb ports removed leaving a parts motherboard for us to salvage the replacement MEC1503 chip. I strongly recommend you purchase at least 2 in case you damage the first one. These boards should look like this:
There are 3 main challenges involved to complete this transplant:
1. Defeating Lenovo's infamous "black glue".
2. Reballing MEC1503
3. Fixing whatever else got damaged in the process.
Lenovo for many years now have been adding a "black glue" that holds down important soldered chips to the motherboard such as the CPU, memory, and our target chip MEC1503. This "black glue" is different from the other glues used by other manufactures (cough Apple) as it is very scratch resistant and immune from chemicals such as IPA (isopropyl alcohol), acetone, nail polish remover, etc. When heat is applied with hot air the glue does soften a bit but still rather difficult to remove without damaging the chip or motherboard. A thin and sharp soldering iron tip works rather well. You just need to be careful to not scratch too deep to damage the traces or solder mask on the motherboard. The glue turns into a grayish-white colored coarse powder when scratched by a soldering iron. In summary, heat + physical force is the only way to remove the glue.
The problem with this method is that it can't be used when the glue is underneath the chip. To defeat this glue to remove the MEC1503 with minimal damage you need a very thin and flexible metal knife to insert in between the chip and the motherboard while heating the chip with hot air so that the solder underneath the chip is molten. The one I got is called "BGA Chip Repair Knife Set, SK5 Steel IC Thin CPU Remover Circuit Board Motherboard Knife Tool" from amazon. There are similar tools on Aliexpress as well.
I strongly recommend that you practice with removing the Thunderbolt controller chips first to get a feel for how much hot air and force is needed. I used 280C at 90% airflow so that the nearby plastic connectors won't be damaged. The Thunderbolt controller chips have much more glue that on the MEC1503 chip so this is good practice before trying to remove the target MEC1503 chip.
When you feel like you are ready, find a side of the MEC1503 chip where there is an opening between the glued down corners. Thoroughly preheat the whole motherboard before focusing right at the MEC1503 chip wait till the nearby resistors/capacitors are loose then place the knife above the chip to heat it up as well. Then stick the knife underneath the chip in the side where there is an opening in the glue. Slowly push the knife forward till the chip pops off.
The removed chip will still have some glue and solder on it. It will look like this:
Next you will need to clean up the chip for reballing. Add flux and use solder wick to remove excess solder and glue. Then apply IPA to remove residue like so.
You will need 0.35mm diameter sized solder spheres for reballing MEC1503. I also used a same sized universal stencil and tape off the holes to match the size of MEC1503.
When reballing use a tiny amount of flux to apply a very thin layer then add in spheres. Remove the inner ring of spheres and center spheres as there are no pads on these locations.
Carefully move chip to a plate heater to reflow solder spheres. Once molten turn off heater and wait till solder turns solid. Then add more flux and reflow again.
Clean reballed MEC1503 with IPA or acetone.
Only after you completed the reball of the replacement MEC1503 should you now attempt to remove the faulty MEC1503 chip on your "whole" motherboard. The process is mostly the same as before but you will need to preheat more since there are more parts on this motherboard.
Now you will need remove and clean the glue/solder on the motherboard. First use solder wick to remove solder before attempting to remove glue. This is where you use the fine soldering iron tip to gently scratch the excess glue off the motherboard.
After cleaning motherboard from solder and glue you will now need to fix any damaged traces and solder mask. Hopefully all you need to do if to apply some UV curable solder mask as I did.
Now you can solder the replacement MEC1503 chip onto your motherboard. Apply some flux and heat with hot-air to make the flux more liquid. Place and align chip to correct orientation. The dot on the corner of MEC1503 should go where A1 is marked on motherboard.
Soldering the replacement MEC1503 is more difficult than removing since you need to heat up the whole board evenly to ensure a perfect installation. I used an IR preheat set to 200C in-addition to my hot air station at 280C.
The chip should sink down into the motherboard and squish some flux to the edge of the chip when this happens.
If everything goes well then you should be good to go to reprogramming the EEPROM but in my case my motherboard did not start up. My usb-c PD tool said the laptop was not requesting 20V and stuck at 5V. Since the motherboard was working before the MEC1503 chip was replaced something must have been damaged in the process or the MEC1503 chip I installed was faulty. I found out that I accidentally knocked off some resistors and a transistor near the "ThinkEngine" chip. After replacing those parts the board finally boots up and I have access to BIOS.
There is one final step to do which is to reprogram the MEC1503 EEPROM. Since the system's identification model and serial numbers are tied the MEC1503 chip the laptop would presume the identity of the doner laptop. This step may not be necessary if you don't mind the error message every time the laptop boots up.
To fix this you need to prepare a usb drive with the Lenovo U1 key. In general you it goes similar to the guide here: https://www.badcaps.net/forum/troubl...ssword-removal
Be sure to use the usbfmtpw.exe program to format the flash drive otherwise the laptop will give you an error when updating the EEPROM such as this:
After the flash drive is formatted with usbfmtpw.exe you need to install "Lenovo Golden Key V3.5.60" from here: https://www.badcaps.net/forum/troubl...r-bootable-usb
Boot into the usb drive and select the "Planar service" then enter in the new serial/model number code in the order detailed in the "T14s - MEC-1663 - Jtag - Pinout - Bios Password Removal" post.
After this the laptop should not have any errors booting up and you have BIOS access.
This is how I was able to replace the EC chip on my T14s gen 2i. The laptop now works great with Linux and I am posting this using said laptop.
There are some specialty tools needed to do this task. The replacement MEC1503 chips can be acquired from Aliexpress. Do not buy the bare chips as these are often fake or unprogrammed. I bought a few "whole board stripper plate" from the seller "Shenzhen Xin Xin Electronics Co LTD Store". These are motherboards that have the CPU, memory, wifi, and usb ports removed leaving a parts motherboard for us to salvage the replacement MEC1503 chip. I strongly recommend you purchase at least 2 in case you damage the first one. These boards should look like this:
There are 3 main challenges involved to complete this transplant:
1. Defeating Lenovo's infamous "black glue".
2. Reballing MEC1503
3. Fixing whatever else got damaged in the process.
Lenovo for many years now have been adding a "black glue" that holds down important soldered chips to the motherboard such as the CPU, memory, and our target chip MEC1503. This "black glue" is different from the other glues used by other manufactures (cough Apple) as it is very scratch resistant and immune from chemicals such as IPA (isopropyl alcohol), acetone, nail polish remover, etc. When heat is applied with hot air the glue does soften a bit but still rather difficult to remove without damaging the chip or motherboard. A thin and sharp soldering iron tip works rather well. You just need to be careful to not scratch too deep to damage the traces or solder mask on the motherboard. The glue turns into a grayish-white colored coarse powder when scratched by a soldering iron. In summary, heat + physical force is the only way to remove the glue.
The problem with this method is that it can't be used when the glue is underneath the chip. To defeat this glue to remove the MEC1503 with minimal damage you need a very thin and flexible metal knife to insert in between the chip and the motherboard while heating the chip with hot air so that the solder underneath the chip is molten. The one I got is called "BGA Chip Repair Knife Set, SK5 Steel IC Thin CPU Remover Circuit Board Motherboard Knife Tool" from amazon. There are similar tools on Aliexpress as well.
I strongly recommend that you practice with removing the Thunderbolt controller chips first to get a feel for how much hot air and force is needed. I used 280C at 90% airflow so that the nearby plastic connectors won't be damaged. The Thunderbolt controller chips have much more glue that on the MEC1503 chip so this is good practice before trying to remove the target MEC1503 chip.
When you feel like you are ready, find a side of the MEC1503 chip where there is an opening between the glued down corners. Thoroughly preheat the whole motherboard before focusing right at the MEC1503 chip wait till the nearby resistors/capacitors are loose then place the knife above the chip to heat it up as well. Then stick the knife underneath the chip in the side where there is an opening in the glue. Slowly push the knife forward till the chip pops off.
The removed chip will still have some glue and solder on it. It will look like this:
Next you will need to clean up the chip for reballing. Add flux and use solder wick to remove excess solder and glue. Then apply IPA to remove residue like so.
You will need 0.35mm diameter sized solder spheres for reballing MEC1503. I also used a same sized universal stencil and tape off the holes to match the size of MEC1503.
When reballing use a tiny amount of flux to apply a very thin layer then add in spheres. Remove the inner ring of spheres and center spheres as there are no pads on these locations.
Carefully move chip to a plate heater to reflow solder spheres. Once molten turn off heater and wait till solder turns solid. Then add more flux and reflow again.
Clean reballed MEC1503 with IPA or acetone.
Only after you completed the reball of the replacement MEC1503 should you now attempt to remove the faulty MEC1503 chip on your "whole" motherboard. The process is mostly the same as before but you will need to preheat more since there are more parts on this motherboard.
Now you will need remove and clean the glue/solder on the motherboard. First use solder wick to remove solder before attempting to remove glue. This is where you use the fine soldering iron tip to gently scratch the excess glue off the motherboard.
After cleaning motherboard from solder and glue you will now need to fix any damaged traces and solder mask. Hopefully all you need to do if to apply some UV curable solder mask as I did.
Now you can solder the replacement MEC1503 chip onto your motherboard. Apply some flux and heat with hot-air to make the flux more liquid. Place and align chip to correct orientation. The dot on the corner of MEC1503 should go where A1 is marked on motherboard.
Soldering the replacement MEC1503 is more difficult than removing since you need to heat up the whole board evenly to ensure a perfect installation. I used an IR preheat set to 200C in-addition to my hot air station at 280C.
The chip should sink down into the motherboard and squish some flux to the edge of the chip when this happens.
If everything goes well then you should be good to go to reprogramming the EEPROM but in my case my motherboard did not start up. My usb-c PD tool said the laptop was not requesting 20V and stuck at 5V. Since the motherboard was working before the MEC1503 chip was replaced something must have been damaged in the process or the MEC1503 chip I installed was faulty. I found out that I accidentally knocked off some resistors and a transistor near the "ThinkEngine" chip. After replacing those parts the board finally boots up and I have access to BIOS.
There is one final step to do which is to reprogram the MEC1503 EEPROM. Since the system's identification model and serial numbers are tied the MEC1503 chip the laptop would presume the identity of the doner laptop. This step may not be necessary if you don't mind the error message every time the laptop boots up.
To fix this you need to prepare a usb drive with the Lenovo U1 key. In general you it goes similar to the guide here: https://www.badcaps.net/forum/troubl...ssword-removal
Be sure to use the usbfmtpw.exe program to format the flash drive otherwise the laptop will give you an error when updating the EEPROM such as this:
After the flash drive is formatted with usbfmtpw.exe you need to install "Lenovo Golden Key V3.5.60" from here: https://www.badcaps.net/forum/troubl...r-bootable-usb
Boot into the usb drive and select the "Planar service" then enter in the new serial/model number code in the order detailed in the "T14s - MEC-1663 - Jtag - Pinout - Bios Password Removal" post.
After this the laptop should not have any errors booting up and you have BIOS access.
This is how I was able to replace the EC chip on my T14s gen 2i. The laptop now works great with Linux and I am posting this using said laptop.
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