Advise upgrading old Sindoh

That was me. Measure the DC output of the power supply of your printer. No stepper driver works with 5V. At least 12V for old printers, like yours.

!!! But just do it, if you absolutely know what you are doing!!!

Please read https://klipper.discourse.group/t/working-with-line-voltage-110-v-230-v-50-v before doing the measurement!