My church has a mid 90's vintage Expression 2X. I know little about professionally running and programming light boards and such, but as a volunteer I run the board for 2 worship services and an occasional special event. I have been an electronics technician for over 40 years now. The Grand Master was defective in the 90-100% range so I volunteered to replace it. A working Grand Master would simplify a few things so I thought it worth the effort. We had it taped up in the 100% position to avoid flickering issues. I ordered a pot from a local dealer and replaced the pot. After powering the board on, it came up with the Grand Master stuck at 31%. Moving the slider has no effect. I thought maybe I'd received a bad pot so I reinstalled the old pot. Same thing. Stuck at 31%.
I checked the old pot with an ohm meter and found it to be 18k ohms with about 45 ohms at the low end adjustment. The new pot read 10k ohms with about 6 ohms at the low end.
The work around has been to disable the Grand Master. I get 100% with no problem to the Submasters. The Submasters adjust from 0 to Full just fine, but full being 31% with the Grand Master enabled is of course unsatisfactory.
Any suggestions?
Also...what's this 789 Startup do. Does it wipe out any programming?
Thanks