Never had this problem with springlines (joy springs) - failure to latch into operatational mode. Not seen this one yet as repair coming in tomorrow but a DD6 with this problem. Previously I've repaired a DD3 with this problem by using an unused gate on the SM, 74HC00 as a pulse-stretcher/ monostable to reliably latch the unit into ON. What is the ageing/drift problem with these foot pedals ?