Welcome to the club! We've been through a belt about every 6 months on our two LT300-MY's. Make sure to order at least 2 of them. We've talked to Okuma about this, but with no luck on a better stronger design.
There are no scales on the X axis, so you will just need to re-establish the Zero on the X axis which is the spindle center aligned with the center of a boring bar holder.
1. Write down your X axis Zero Set #.
2. Position boring bar holder to spindle centerline.
3. In Zero Set, CAL 0 for X axis.
4. Calculate difference between old # and new #.
5. Adjust PR ZERO OFFSET for X axis by this amount in your SYSTEM PARAMETERS. (You will get a power on effective parameter set alarm.)
6. SET Zero Set back to original #.
7. Cycle power. (If older control, you may need to press Backup key first.)
You should be good to go now.
If you follow this procedure, you will not have to reset your variable limits or stroke end limits or change any paperwork or programs that have Zero values in them. You may need slight offset adjustments depending on how accurate you find zero again.