Probably laser, or/and servo control board problem, time for a specialist, my guy is in Sweden ! There is a good guy in Holland too.
If you want to try yourself, next step would be replacing the laser head, but it is really easy to mess up a new laser if you don't know what you are doing.
If you want to try yourself, next step would be replacing the laser head, but it is really easy to mess up a new laser if you don't know what you are doing.