BTT Quality Control

I’ve heard countless comments about Big Tree Techs poor quality control, but I had never been hit myself until today.
I’m installing an SKR 1.4 turbo with TMC2209’s using UART for my lowrider 3 build. Finally got the firmware uploaded after finding an SD card that worked, and was excited to see an axis move, when it booted up to display “TMC CONNECTION ERROR”.
M122 reported all drivers ok except X, “Testing X connection… Error: All LOW”
Spent over an hour trying to nut it out. Swapped drivers around. Rechecked jumper pins. Tried different compiles of marlin, right down to a plain vanilla version straight off the Marlin github, all with the same problem.
Eventually stumbled upon someone else who had exactly the same problem as me. They narrowed it down to a hardware fault and worked around it by changing the pins file to move the X axis to E1 driver. I did similar, swapping the X and Y drivers in the pins file. Sure enough the problem followed the hardware and not the firmware, and now I had a Y axis error.
I need all 5 drivers, so didn’t have the option of just using another one. I went as far as finding the datasheet for the processor and checking all connections I could between it and X driver socket. Lucky its not in a BGA package so you can access the pins, but all were OK anyway. Then checked to see what pins were common between all the drivers, and sure enough one of them (the first one in the black row) was common between them all except X.
Unplugged and de-mounted the board from its enclosure, while thinking I might have to run a jumper wire underneath from one of the other driver sockets and see what happens. Flipped it over and was pleasantly surprised to find the pin header hadn’t been soldered on. Soldered it up and put it all back together, worked straight away.

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Now i know where our former quality control person went to… :joy:

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