Power card is always the culprit. Q1 is a very tough solid state device that never fails by itself , 5+ years working on Raymond's I came across this issue multiple times. The aluminum heat sink block that Q1 is mounted on could be shorted to the frame. It has a special foil to prevent it but if the screws come loose or were ever removed there is a good chance it was damaged. I always installed rubber washers underneath it instead of the foil. That is not recommended by the factory but it works alot better especially if u have holes or cracks in ur floors. Covering the power card completely front and back with dielectric grease helps in preventing shorts in the circuits from moisture or dirt particals. The EZ trucks are super sensitive to static electricity so make sure u replace drag cables or static straps. Bad batteries also induce alot of static into the frame. I had customers remove , pressure wash and paint with rubberized undercoating if they did not change batteries and never have code 23 come up again.