You would need to remove the spindle cover and remove the belt, then spin the spindle by hand, it should run loose. You could also run it in the air without the spindle belt attached to see if the motor spins up or if it stops and starts. If this is the case then the spindle motor is more likely.

The lights would suggest its either the material missing or the pinch roller positions, try covering the front and rear paper sensors.

Is the spindle spinning properly, if it was jamming the cutter could be forced through the material causing the material to melt, have you tried a different material like wood, to see what happens.

If your UK based contact the RolandCare team on 01275 335540, they can send you the latest version of installer.

I haven't seen any burnig like this previously, adjust your speed and depth settings for this material.

What material are you using?

It's likely the head, it is sometimes caused by ink misting.

Contact your local roland office, they can give you a download link, only the original VersaWorks will work with the XF-640.

Contact the RolandCare team on 01275 335540, it could be an internal cable getting caught causing the head to not reach the correct place of impact.

It will likely need an engineer visit to look at the power issue, without this it will possibly not get any further.

Speak to the RolandCare team on 01275 335440, send them the files so they can try to reproduce the error and let them log in and see what happens, this will help for a quicker fix.