I got a pretty beat up DESKMES remote for the Durst L1840 chassis. This is a little box with 4 switches that duplicate the 4 up/down switches on the Durst control/timer unit. This little box is very handy for focusing wall enlargements because it has a long cord. It also comes in handy when doing vertical enlargements with the baseboard near the ground.
On my unit all 4 of the switches were busted.
I found an exact replica of the switch here: