The TFT28 clone that the Artillery Sidewinder X1 uses requires +5v to operate. The original from MKS has an optional +12v input for power, but Artillery's clone does not. Normally, it gets the +5v from the controller's AUX port, but I need to disconnect that and redirect those serial pins from the TFT28 elsewhere. The good news is that on both ends (both the MKS Gen_L AUX port, and the connector on the TFT28), there are spare +5v and GND pins we can use. I wired up a couple of 1x4 dupont connectors with positive on one end, and GND immediate next to it, leaving the remaining two pins empty. I made this cable the same length as the existing cable between the controller and the TFT, and swapped them out. Here's a couple of pictures for orientation:

With power squared away, it was time to connect the serial cable I made earlier. I threaded it in through the hole in the back where the Y end stop enters the case, and routed it along with the rest of the cables. Once I got it to the TFT, I connected it to the other half of the connector that was previously connected to the AUX port.

When I went to plug it in, I found that I had TX and RX reversed from what I expected and had to swap them. When I pinned it out, the only doc I could find was the pinout for the AUX port, and I had based it on that, forgetting to invert TX and RX. Oops. Thankfully the PCB is labeled to the side of the connector.

Sadly, when I reassembled the printer and tested it all, I had no serial communication. The TFT powered up, but it wasn't updating the temperatures on the display or sending g-code to Klipper. I've got a couple guesses as to what is wrong:

1. Baud rate - Klipper is operating at a different speed than the old Marlin firmware was, and the TFT firmware needs to be updated to match
2. Despite all my planning, I still have TX and RX backwards. It has been my experience that you can plan all you want, it's still darned close to 50/50 that you'll get it right.

Ideas for troubleshooting:

• determine the default baud rate for the TFT and reconfigure Klipper to use that
• find another serial-TTL adapter and emulate the TFT, does the system even work? If so, emulate the other end, does the TFT work with the serial-TTL adapter? Probably should have checked that before I started >_>