first off two servos can never be plugged into the programmer at the same time. the programmer can only see one servo at a time for programming and will get confused if it tries to talk to two. you can sweep both at the same time but not program. check to see if your white signal wire is intermittent connection or try plugging into servo connection 2 of the programmer, possible bad solder joint. as for anything else I would have to see you use it to see if anything was done wrong.