User Chris P observed poor quality engraving - specifically grainy edges and an uneven "woodgrain" type effect in engraved areas.
Chris, if you are out there can you share a pic of the results before I did this? helpful for diagnosis.
This was remedied by servicing the carriage. Here I will share what I did. This video from today that covers the process performed yesterday.
First: Read the Zing book. Really. It's good. It contains lots of great tips and tricks and will address 80% of problems. Youu can find it in the drawer labeled "Laser stuff" next to the laser.
Second: If it between 8am and 7pm on a weekday, call zing tech support. They are great and nice and helpful and great teachers.
Inspecting the carriage
Removing the carriage
Servicing the carriage
More about the carriage
Replace the carriage