My R4331 will only raise to about 4 inches, and won't lower past roughly 1.5 inches. To my knowledge, this just randomly happened. I will say that many of the original screws and hex bolts have become loose in different parts of the planer. I am constantly having to tighten, so not sure if maybe a bolt came out somewhere and I just can't see it, or if there is a troubleshoot for the problem. Anyone else had experience with this?