superdrive tray open

all fixes gratefully received,

my ibook g4 14'' superdrive won't physically accept a disc, not even halfway, there is something hard and metallic blocking the slot. if i open toast=recorder settings=select superdrive=record it says tray open.

i'm guessing that it's failed mechanically unless somebody here knows better.

i've already ordered a lacie firewire external dvd drive, because i know that to install osx and boot from disc, an external drive needs to be firewire. so in the event of catastrophe i can recover.

i can open the thing up and replace the internal drive, i've done it before, but the external is the same price, more flexible, less risky, and if i sell the ibook will hopefully be compatible with any new mac.
tried pmu/pram reset, power/mouse hold, power/f12 etc. and am now out of ideas.

thanks in anticipation
steve