Our Gorgar did this, Time Warp, Scorpion, and a couple other system 6s have done this. We have checked and changed and rechecked switches, diodes, connectors etc. it will go away for awhile and then just do it again...as Neurkinetik said I think it is just a system 6 thing. No reason that we have ever found, just a glitch in some system 6s and 6As. We have some system 6s and 6As that have never done it. It seems to be just a system 6 or 6A thing no system 7s we have had have ever had this issue...
Phoebe