Durst 138S 5x7 enlarger foot pedal.

[GregY]

There are two different locks to the vertical baseboard travel. The general unlock is via foot pedal pressure. Then there's a secondary tightening knob on the side of the baseboard (and yet another knob for fore/aft centering). The tilt lock is a lever is on the side. The big knob or lever underneath is for attaching the baseboard to the main arm.
I personally use a supplemental dumbwaiter cable and weight to compensate for a heavier than normal colorhead.

I don't know if Glenn Evans is still in business. He was attempting to retire. But you could trying calling him to see if he has any leftovers.

Thanks Drew!