Happy Ending to an expensive worm gear slide out problem`

Chances are it melted its solder due to high current draw due to binding. Or the motor itself could be too small for the job...

Get yourself a clamp on current meter and watch the current draw on both the in and out travel. You may be able to get the guy that fixed it for you to find out what the locked rotor draw is and suggest what the average current draw should be for the motor.

Point is, it's not common to melt the solder in the armature. So you would be wise to find out whats causing it to get that hot.