I'm still using a QC1 without any problems. Try re-routing the antena wire so it doesn't touch anything including the chassis. Do you have the blue wire connected to anything? It it used for, like in 12th scale mod, when you're using an external power source for the electrics. I had a problem once with the signal wire being lose inside of the speedo, I soldered in a new set of wires and it's been fine since. It doesn't sound like you problem has anything to do with that, but you never know.