hi! im having a kone elevator with tms 600 and v3f20 invent.the elevator suddenly stop working and at the display shows drive unit fault red led.also on the inverter display i got cpu on cpu ok but not v3f ok on mode 2.on mode 1 i got b.res blinking led.i replaced the inverter board with a working one but the problem still exist.after some power on and off and some resocked conectors on board iverter the elevator started but after 6 hours it stoped again with the same error.the elevetor is in a cruise ship.any help appreciated