DMM Closed Calibration

[Tel007]

Hello Guys,  I have a  MORPILOT 108C   DMM  that is reading 0.2 V DC high so was looking at recalibrating.  I decided to tear down the DMM and have ago at adjusting but found no trimmers so it is as I now understand a closed system. I found open contacts on the pcb marked CAL  SW1. I bridged this reassembled and powered up.  This obviously put it in calibration mode. When switched to ohm/resistance CAL was displayed and then stepped through values starting at 8 and ending at 92.  After this it displayed ER3 which is a common error code so assume it was exoecting an input. If the orange SELECT button was pressed during or after the step sequence the display went to 0000 mV.  Any help or info to progress this would be much appreciated... pics attached for info