LG DVD player - disc will not load / showing disc error for all discs

In most cases when the CD does not play it is possible that the optical head is a suspect. Sometimes it might pick up ordinary audio CD but will not play other formats. This indicates that the optical head is weak and so there is no detection or scanning of the CD . If the optical is working the tracks will be read immediately but with no scanning the laser head can be defective.
Sometimes certain cleaner disks will not be tracked to run for cleaning as it will not be read and so will reject. Hence it is ideal to manually clean the laser head eye using a cleaning swap /cotton bud with gentle pressure on the lens eye.
If there is no result then watch if the CD spins or tries to spin. If so the board seems to work unless a test is taken on the main board but the possibility of a defective optical head can be the suspected fault.
If any of the above seems otherwise we must recheck with possibilities of a malfunction of the main processor board