found a topic from 2023 that had this as an answer in Help with board connection
No Printer Attached is the error message that the TFT gives put when its queries on the serial port are not answered in the expected format.
This can stem from several problems.
- The black serial connection cable is incorrectly installed. This is a 5 pin cable and must attach to the correct UART on the screen PCB and on the SKR Pro board in the correct places (see docs.) One simplistic and incomplete test is to see if the reset button on the TFT resets the SKR. This is the 5th wire on the black ribbon cable that is separate from the other main 4.
- The connection speed is incorrect. This is determined on the TFT side in the config file. It is determined on the SKR Pro in the Marlin configuration.h file. V1 firmware sets this to 250000 baud.
- Firmware is incorrect. The V1 firmware enables the TFT serial UART in the Marlin cinfiguration, and the TFT comfiguration file.must also enable that serial communication. Note that Marlin Mode on the TFT does nkt even need this connected in order to work. Also only the matching Marlin firmware will respond in a manner that the TFT will tecognize. For example, RepRap Firmware can be installed on the SKR Pro, but will end up with the “No Printer Attached” error because the reaponse format for the status query is different.
if we go with this answer, the proper behavior of of my machine would go with 3, it might be the TFT screen firmware
(I’ve tried multiple connection ways and my current one is the only one that works, and Marlin mode works as well, touchscreen gives the No printer attached problem)
edit: thought it was firmware, decided to flash the screen with BigTree latest firmware, still same problem.
Pics on connection, so far I can’t seem to think there is something wrong in the connections…, the RESET button on the board resets the screen, and the board is clearly the TFT connection.
edit 2:
found this post as well
tried Ryan suggested fix
Unplug everything except power and the black TFT cable (unplug the gray ones). Try it again. These files have been used and tested for a very long time so it is not the file. we need to figure out why yours will not use it.
still same problem, I’ll keep doing research and figuring how what’s the issue here, I really don’t want to make a custom firmware or buy another board “just in case” the board or the screen is defective…