Proform 2500 belt not spinning fast enough?

My Proform 2500 belt doesn't spin fast enough. If I have the speed set to 10 it appears to only spin at maybe a 2 if I'm lucky and thats with no weight on it. If I stand on it, it will stop. I removed the lid and it does not look like it is slipping nor is there and rubber shavings or dust inside from the motor belt. I checked the reed. I tried making adjustments to the belt tension with no change.
Any suggestions?

Thanks Jeff D