On a door from this era, the first thing we check isn't the opener - it's whether the torsion spring is original or already a mismatched replacement, since a lot of these doors have had one bad swap done at some point that never matched the door's actual weight. Getting that right is most of the job.
We lubricate the track and rollers, check cable wear at the drum, and test the balance by hand with the opener disconnected - a door that doesn't hold position halfway open on its own is telling you the spring tension is off, regardless of what the opener motor is doing to compensate.
Here's the limitation: if the door itself has cupped, rusted through at the bottom panel, or the track has warped from age, maintenance won't fix that. At some point on a door built in the 1950s, patching the spring and rollers is treating a symptom, and we'll say so rather than run up a bill on a door that's due for replacement anyway.