LiteOn lh-18a1h DVD Read/Write problem

vbimport

#1

Got this drive from a friend and check why this drive cant read/write a dvd, ive flash this from HL03 to HL09 then back to HL06 and still cant read any dvds

i also open the unit and blast a jet of air onto the lens and other parts for dust buildup. after that… it can read a cd upto 12X and no read for DVD disc… what do you think the problem could be?