problem x 3

[PUBBY]

can anyone help me with the following :
i have got three different playstations to try my back-ups on and they all come up with different results,
all three playstations have been chipped and i am using a yamaha 4416s writer with clonecd and verbatim 80 mins cds. one playstation wont play some of them at all, one will only play some if you turn the playstation on its side or upside down and the other will play most of them but then if youtake it back out and put it back in again it comes up with please insert disk ?
these problems seem to happen at random with any of the playstations even on games that i have had for ages, somebody told me that the reason was the laser on the playstation was worn but one of the playstations is only 2 weeks old and has only been chipped for 2 days.
any help would be greatly appreciated.