Replacing old Liftmaster 1/2 hp drive

The Liftmaster system is over 30 years old.  The doors are heavy wood 4 panel.  A couple of days ago it stopped opening as the first panel bottom rollers were starting into the bend of the track.  If I help it up it opens.  It closes fine.

I am wondering if the motor is getting tired after 30 years of pulling the heavy door up.  It looks pretty straight forward to replace the drive.  Amazon sells a Liftmaster drive for around $200.  That seems like a better deal than calling a service company.

So a few questions:
Does a tired motor sound like the problem?
Is the Liftmaster the right unit to replace it with?  Are there others?  Is the chain drive universal?
Any other tips or suggestions?

Thanks,
Brian

I am wondering if the motor is getting tired coaches after 30 years of pulling the heavy door up.  It looks pretty straight forward to replace the drive