HELP! I have a Durst CLS 450 that won't turn off

Discussion in 'Enlarging' started by Eric Rose, Feb 17, 2018.

  1. Eric Rose

    Eric Rose Subscriber

    Nov 21, 2002
    Calgary AB,
    Multi Format
    I have a Laborator 1000 with a CLS450 head. The head is driven by the Durst TRA450 control unit. The timer is an Omega timer. I was making test strips and suddenly the light would not turn off. Even when I unplug the the timer it still stays on. The only way I can get it to turn off the enlarger light is to turn off the TRA450 unit.

    I have the schematics of the TRA450 unit and figure it might be a relay, but who knows I haven't pulled the case off yet.

    Any suggestions? Has anyone replaced the TRA450 with a newer switching power supply?