On a building from around 1985, the fix usually starts with the spring, not the opener. If the door won't lift, or lifts and slams down, a torsion spring sized for the original door weight is the first thing we check - and on a bay this age, replacing both springs on a double door is standard practice even if only one has failed, since the other is on borrowed time.
If the door is a single-skin steel panel rather than insulated, dents and rust at the bottom panel are common by this point and sometimes it's cheaper to replace just that panel than the whole door, provided the manufacturer still makes a matching one - which isn't guaranteed on a door this old, and we'll tell you straight if we can't match it.
Opener work on Mableton's commercial buildings usually means checking the travel limits and the force settings before touching the motor itself, since a door that's been repainted or had panels swapped can throw off the balance the opener was originally set for. We don't replace an opener that just needs recalibrating - that's the honest call, even when a new unit would be the easier sale.