My field is sound not lighting, so please bear with me. I was doing sound for a show at our local school and noticed that when the lighting guy brought the master fader up it would flash momentarily before dimming again and gradually fading up as it should. It didn't happen every time but I thought it was likely to be a worn or dirty fader. I've replaced audio faders before and thinking "How hard could this be?", I foolishly offered to fix it for them. Soldering in a new fader seemed to be straightforward, but the desk doesn't work now.
All the LCDs on the flash buttons are lit constantly on channels 1-6 on banks A and B, and none of the faders appear to do anything. With a bit random button pressing I did get it working in a chace, and the Master fader worked then, but that's the only time I saw any of the lights come on.
I tried a desk reset and it didn't make any difference. I have until Sept 5th when the schools go back to get it working! Any suggestions gratefully received!