This sounds exactly like the problems I had with an inherited 1+ a few weeks ago - I got very few successful prints, mostly blobs. Having never used the 1+ before, it took a while to realize that the peel motor was stuck, and needed replacing. After describing my issue and troubleshooting to Formlabs support, they sent out a new motor for free within a few days. Try contacting them!
Check my post history for some more background on the issue, and search around for how to open the printer and have a look at the peel motor. If you hold the shaft still when turning on the printer, the shaft should move up or down in relation to the motor body.
Edit: Here’s the whole ticket explaining my issue to Formlabs support:
Original request for Case #00570395:
Hi! I have a Form 1+ where the tilt mechanism has stopped working. I have done a good amount of testing, and narrowed it down to the tilt mechanism stepper being defective.
Symptoms are: During tilt stage of print, stepper shaft only vibrates (looses steps), does not pull down.
The most important tests were:
Test A: disconnected tilt stepper from tilt mechanism at the small black screw holding the shaft to the tilt coupler. This allowed stepper to freely rotate its shaft without issue.
Test B: With shaft disconnected from tilt mechanism, I kept the shaft from rotating with a pair of pliers. I would expect the shaft to then move up or down, but the stepper cannot overcome its internal friction and starts loosing steps instead.
My current theory is that this friction has to do with either worn out bearings inside the stepper, or spilled resin/debris inside the stepper.
I have been looking at resellers of the specific stepper, but they seem very hard to come by these days. Are you able to point me in the right direction, or even supply a spare part for me?