I bought 200+ Raspberry Pi Model B’s and I’m going to fix them! Part 3

Introduction

In my last post I mentioned that I was unable to continue the repairs on the boards with failed Ethernet due to waiting on solder wick to arrive however I found some in a draw!

I have 12 boards that I know have a failed Ethernet chip however upon diagnosing some of the boards that won’t boot I noticed that a fair few of them have a short to ground, I spent some time diagnosing this and after removing countless components on a donor board I discovered that this short was coming from the Ethernet Chip – Maybe another common fault? Removing the chip and associated components allowed the Pis to boot and they are fully functional otherwise.

Removing the Ethernet Chip

Removing the Ethernet chip is no easy task and certainly not recommended for an amateur although what better way to practice is there than removing surface mount components than on a old Raspberry Pi ?

I started by covering the board in aluminium foil and cutting around the Ethernet chip with an X-acto knife. I then set my YORKING 858D Hot Air station to 265 degrees C and heated the chip, gently nudging it from time to time with a small pair of tweezers. It eventually lifted from the board after around 3 minutes.

The PCB after the Ethernet Chip was removed
The removed Ethernet Chip

I then proceeded to clean up the PCB and remove the associated components. I have created two diagrams which are shown below. The components highlighted in red need to be removed, the ones in Yellow need to me moved to the locations highlighted in green:

Components to remove (Top)
Components to remove (bottom)

Once I had removed all of the components above and moved the two resistors highlighted in yellow to allow the USB port to function I cleaned off any remaining solder and flux before covering the area in fresh solder mask to protect it from further shorts.

Applying the solder mask
Solder Mask Applied

I then cured the UV solder mask using a LED UV light and covered the exposed pads on the bottom of the board.

Conclusion

Whilst loosing Ethernet is a shame this is an easy way to revive what I expect to be a large amount of the Pi’s that won’t boot. Other than loosing Ethernet there is another negative – the Top USB port will never work again however I will likely replace the USB ports with a single port like the original Model A before sale.

Check out my other posts on the 200 broken Raspberry Pi’s below:

Part 1

part 2

6 comments

  1. the board level repairs, so great. Maybe It’s easy to fix in china. I’ll try to find the team for this project. dawson you’ll have chinese partner, it’s me.

Leave a comment

Your email address will not be published. Required fields are marked *