my scroll saw started sputtering and making noise like it wants to stop working. that's after it had been working fine the previous 20 or 30 minutes. the tension seems ok it has had its routine oiling. I blew it out with my shop vac tried again it still acted the same way, just replaced my bellow a week ago. kinda wondering what's wrong. is it tension related or is the brushed worn out in the motor?

any advice would be helpful