Indesit WIL133

This machine was in use at a local bowling alley for overalls etc. They have a service contract and called in the insurers engineer to change bearings (sealed tub change). When the machine was back together it didn’t work so they renewed the module twice then gave up. The bowling firm were given a new machine but left with the old one, which was susequently brought to me to have a go. It came with one new module (in situ) plus the original one, loose. My first thoughts were that the new board might still contain an unprogrammed EEPROM or an incorrectly programmed one so I tried the old module. This was sparking at one of the solder through joints under the socket for the interlock plug. This was not related to the interlock itself as it still sparked with the interlock plug removed. I unsoldered the socket, repaired the solder through link and put it back together. You can select a programme, press the start button, but the door locked light just flashes, although the door is locked. It’s exactly the same with the new module fitted. I changed the interlock and checked continuity of the interlock wiring. Any thoughts?