Hi Kevin. Yes If it's just lacking power then it does sound like a belt issue. Possible the intermediate pully has lost it's spring tension, the springs were pretty soft. Check the belts haven't gone thin due to wear.
Also something to look for is make sure both rollers are driving, if only one roller is driving that can give you a similar lack of power feeling.
Also something to look for is make sure both rollers are driving, if only one roller is driving that can give you a similar lack of power feeling.