Studio Color 575 - Lamp Won't Douse

Hi - new member here. I have a Studio Color 575 that's developed a problem where it won't douse its lamp. It has no problems striking the lamp or keeping the lamp running consistently throughout shows, however we've been having to pull power to the fixture entirely just to get the lamp to extinguish once showtime is over.

This "non-dousing" problem occurs whether trying to douse from a DMX command, manually activating the "L OFF" command from the on-board menu, or simply removing all DMX signals to the fixtures (which auto-douse all the remaining Studio Color and Studio Spot fixtures we have). None of these actions results in the lamp dousing.

Any ideas? Is there a specific component on either the LPS, main logic board or arm-mounted trigger card that controls dousing and has gone defective?

Thanks in advance!
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