What's wrong with the wiring / connections of the machine's electrical panel ?
1) the electric tester doesn't light up when connected to the 230 V AC phase (supply) , but the DMM connected to the Phase 230 V Ac phase supply & to the neutral ( Neutral is common in the whole panel ) of the panel shows the full voltage of 230 V AC
2) the 24 V dc coil contactor , shows the output of about 82 V AC w.r.t the neutral while there is no supply at the coil of the contactor (means the supply is switched off by means of selector switch) i.e. the coil is not energized and giving the 82 V AC .......... although it should have been given the output of 230 V AC when its DC coil is energized with 24 Vdc supply given by the selector switch.
if you use a DVM, they have an extremely high input impedance, so they will measure any leakage path from 230 V as a voltage. For instance in the UK you are allowed a leakage path of down to 10M ohms,as most DVMs have an input impedance of 10 M, they will read 230V/2 = 115V due to a minimum spec. leakage.
Frank