Loss of synchronization between the left and right material feed chains can occur when there is a disproportional amount of load on the side or the other.
The encoders work to synchronize the two sides of the Retro C. If the saw loses synchronization or stalls it could be something mechanical, it may be that one of the encoders is starting to fail or it could be the connection of the encoder to the motor has broken. This article will teach you have to replace the encoder.
If the scrap belt is slipping on the roller or not staying centered manual adjustment is required.
Step 1: Remove the gray chain guard so you have more room to work. There are two bolts on the right side of the cover that hold it in place. Once the bolts are removed it slides right off.