Vitamaster treadmills are not popular purchases any more, so finding information and repair manuals online can be difficult. This treadmill has some of the same features as the Roadmaster or DP treadmill and is also susceptible to some of the same repair issues. When troubleshooting the Vitamaster, start by checking the belt first, as this is usually the problem. If the problem is not resolved by replacement of the belt, then continue and check the motor.
Check if the belt abruptly slows down after a few minutes. Place the treadmill on the lowest incline. Walk at 3 miles/hour and pull out the safety key. As a rule of thumb, it should take two or three full steps before the belt stops.
Place the treadmill on the highest incline and walk at 3 miles/hour. The belt should continue to turn evenly and smoothly.
Check whether the belt is sluggish at the lowest incline but operates normally at the max incline; if so, it is worn and needs to be replaced.
Connect an 18-volt battery to the treadmill motor. A cordless drill battery is a good choice because you can easily connect the red and black leads on the motor directly to this battery. The motor should run at 1 mile/hour.
Connect a 12-volt car battery to the motor if you don' t have an 18-volt battery handy. The motor should turn very slowly, but you should be able to walk on it. If either step 4 or step 5 fails, the motor should be replaced.