Hi RDS Locs all work fine, I have tested them (removed chip and run on DC) With Loco 1, it doesnt matter what is keyed in, Loc 1 runs. Funnily enough, I had started testing three of locos straight from the controller and had them running and then they just stopped. Went back to basics. Set up a circuit on DC, with non chipped locos and then when that working connected up controller. Had loco 1 running for about 20 mins. The yellow error light comes on a lot when keying in other locos and cannot be cleared unless switched off and on. My thoughts are that keypad is the fault and would have opened up if there had been easy access. For the record, I have built my own PC back in the day so a bit familiar with internal gubbins of techi things.