I have an unmodded V9 (model 50003). Its has stopped reading DVD's, but still works fine on cd's. Tried the usual lens cleaning (no different). When I switch on with the cover off, and no disc in, the laser seeks it's start position, gives one red flash, bobs up and down twice, then settles into its default position, I think this is right ? The laser height adjustment is the one with two camwheels, I have not adjusted the height at all. Laser is a Sony KHS-400C.