Hi sir:
The best way to Reset the unit , coming for Mercotac, or Weko, is resetting the CPU, in the unit for microprocessor
see my own formula how to do it, in very simple way, only look for the Type of Microprocessor or CPU, Intel, or Motorola, look Data sheet Pins, via Google, or Bing, or other Browser, and locate Pin: RST or Reset, and look GRND or Ground.
See my own formula schematic ,trace a bridge fro RST to ground, with the Machine ON...!!
Good luck