The school I work for has a Bullfrog which has been permanently working in our theatre for the last few years. Just recently it seems to have developed an issue, whether this is a childs' meddling hands or not I'm not sure.
Problem: The grand master fader is completely ineffective, it doesn't fade the brightness of anything, the submasters and channel faders work but the only way to dim them all at once is to use the A or B Masters.
Could this be a different mode setting that I'm unaware of or a mechanical fault?
Thanks very much
Sam
ETA- We have just installed the latest OS 10.12 which has made zero difference