I have had my chair for about 2 years now. The other day, after having 0 issues the entire time I have owned it, the tilt mechanism seems to have broken somehow.
When sitting down the base tilts forward as far as it can go. This can be reset with a good deal of effort, but will immediately tilt back when sitting down again.
The lever that enables tilt adjustments remains locked and does not impede this unwanted tilt, nor does the stiffness control knob. I cannot see anything structurally wrong with the chair, at least without taking it apart, but am not entirely sure what I would be looking for, anyways.
Hopefully someone can help me out here; I would really want to avoid having to throw out this chair.

