Schwinn Airdyne - how to fix belt alignment for fan wheel?

[scw2]

At the recommendation of some of the home gym owners here and elsewhere, I finally picked up a used airdyne to work on my cardio. I believe it's an AD5/comp which is an older model with a chain drive for the pedals but a belt drive for the fan wheel. I took it apart to clean and repaint the bike, and after I reassembled it the belt has an issue where pedaling will start causing it to drifting left on the gear until the belt completely falls off.

Anyone have any ideas what's going on? Is the issue with the gears not being set properly in the frame, or is it an issue with how I installed the fan wheel itself? Not sure if anyone knows what things to try to trouble shoot this but some people on the forum are mechanically inclined so hoping for some crowd sourced wisdom.

I've included a picture of the belt where it's already starting to shift left.

[0ddl0t]

just spitballing, but have you tried flipping the belt's gear/pulley around? Maybe it is slightly asymmetrical?

[UNK]

Put a straight edge across the pulleys to check alignment.

[JCN]

Looks like you can adjust alignment of the pulleys.

[JohnO]

Assuming no bearing slop:

In order for the belt to track true without wandering off the gear the Fan Wheel axle and the Gear axle must be perfectly parallel to each other. Given what is shown in the picture it suggests the axles are not parallel. The viewed side of the gear axle needs to move slightly to the right or the opposite side to the left. Can you adjust the bracket it sits in? Only one side because you need to change the relationship not increase the distance with the same skew. Or conversely the positioning of the fan wheel must be adjusted. I would check the Fan Wheel position first.