Help!! Pentax MX Issue

I recently dusted off my Pentax MX that has been in it's bag since 1997 or so. I gave it to a local camera tech to check it out before I used it and he said it was functioning fine. After putting a test roll of Tri-X 400 through it last winter I had this dark swath on all the negs, from very subtle to very pronounced. I am thinking it has something to do with the shutter curtain? What do the experts think? And who do you recommend for a repair tech? I love this camera, we have been to 4 continents together way back then and she has the scars to prove it.

I agree, looks like shutter problems. Eric Hendrickson is the go-to man for Pentax here in the US. His website is http://pentaxs.com/

My Dad had a very similar problem years ago on an Exakta Varex. It was a shutter problem, IIRC the second (closing) shutter curtain was "catching-up" with the first curtain and reducing the exposure on one strip of the frame.....worse on faster speeds, which may account for the variation from very subtle to very pronounced ?