Drum does not rotate - Whirlpool LGB6300 Gas Dryer

That error indicates a failure in the rotation of the main motor . Please check if the drum unit rotate normally. Just remove the drum unit and check rotation. If drum unit is good, check the main motor

This means that one of your drums has exceeded its life cycle (carries toner from the cartridge) and generally run around $100 +/- to replace.

Check if the lid isnt working as this prevents a roration . Else must be a loosened or broken belt that rotates the drum as the motor works . Hope this helps

would not lube the drum but the two small wheels that the drum rotates on sometimes their "axles" get dry and rusty and will squeak. Put some antisieze on them and see if the noise goes away.

You will need to remove the drum and assembly, please check on this link for tips: Drum removal

carbon brushes in motor

Fisrt, see if you can rotate it by hand, BOTH directions. It should have some resistance. If you can spin it and when you stop pushing it will turn a full turn, your drum belt is too loose. If the belt is good and tight, it will spin less than one half rotation, there is probably something blocking one of the wheels that the drum rides on.

put few clothes in it drum to switch on its ball in there

When you say it won't turn all the way on, does that mean the drum isn't rotating?

If yes, the belt from the motor that goes around the drum might have broken and you can hear the hum of the motor spinning but no longer rotating the drum.

The other thing I can think of is that the motor itself has failed, possibly seized, and you can hear the motor trying to spin but it cannot. With the dryer unplugged and empty of clothes, try to rotate the drum. If it rotates extreamly easily, then the belt has broken. If you cannot rotate it at all by hand, then chances are the motor is seized. It should rotate with moderate effort.

im confused as to why you think no drum rotation would be caused by bearings. typically worn bearings would cause noisy spin. only if bearings were completely seized would that cause no drum rotation. can you rotate drum by hand? if so bearings are not seized. can you hear motor rotate when you select spin? if not, then likely cause is motor brushes. do these simple tests and get back to me if you want. and bearings are quite difficult to replace on this machine