BU40N not reading DVDs

[thepwrtank18]

My patched BU40N isn't reading DVDs, producing a loud screeching noise instead. No sign of damage on the DVDs. Blu-Rays screech but read fine, and BDXLs can read with no effort at all.

CDs play fine, as well.

[zittrig]

Try to clean the lenses with alkohol and a q-tip. Let the alcohol not dry by air.