No output to mains and a few other things

[JohnW63]

Up front, I am an IT guy not a mixer person, but the high school keeps grabbing me for these D8B issues. A apologize for ignorant questions.

There are a few issues, I need to figure out and I hope it is just that the students have messed up the settings on the mixer or in the software.

1) I get nothing out to the mains.

The odd part is that I only get sound out the near field monitors if the given channel is set to Solo. That doesn't make sense to me. That should send ONLY that channel to the output, if I understand this stuff. The symptom that the students showed me is that there is an amp in the rack, that if it goes to "protect" mode, no sound comes out of anything. The confusing part is that this amp is NOT one of the power amps that feeds the mains or other speakers. The input of the amp is from a graphic EQ and the output goes back of the main cable of many wires that plugs into the D8B. Why would the D8B get signal from the output of an amp ?! There are 4 pairs ( 8 wires ) coming of the stereo 4 ohm output that goes back up what I call the snake cable to the D8B.

I have tested the amp with an iPad min as an input and a single speaker as the output and it works and does not go into protect mode. So, I think the amp is OK. What exactly it is doing in the signal path is my confusion.

2) Why do I get nothing on the monitors UNTIL I hit a solo button on a channel seems wrong. Am I missing something ?

[Crash]

Are the channels assigned to the master bus?

[JohnW63]

I know the channels are assigned ( buttons lit up ) and I have the L-R channel pressed. Is that the only thing I would need to do to complete the assignment ?

[Crash]

OK, having re-read all of this with the oddities of the amp wiring, I would re-wire it all so it is correct and makes sense. I can not think of a reason to ever send the output of an amp into the mixer. If you can see activity on the Master bus with a channel assigned there, then the issue is not the mixer I wouldn't think.

[JohnW63]

If you can see activity on the Master bus with a channel assigned there, then the issue is not the mixer I wouldn't think

I'll try to do some signal tracing and see exactly were the lines go. The more I think about it, doesn't the main umbilical connection from the mixer go to the rack mounted computer ? It could be these lines go back , after the equalizer, to the mixer for monitoring, but why have an amp in there ?

What about the issue of needing to press the Solo button to have the audio come up on the monitors ?

[Crash]

There is a db25 data cable and the big ass connector that carries power, both go to the CPU/power supply. You couldn't hook an amp into those lines.

Without hitting any solo buttons, are you seeing any activity on the master L/R bus meters? I am curious as to if you are able to control the montor volume with the Speaker Level Vpot. I am trying to suss out how you are feeding the monitors...as in from what jacks on the console.

It is hard to troubleshoot this one via the web and written word.

[JohnW63]

I got it working and a learned a few things.

1) Don't always believe the students who run a high school mixer about how things work.

The amp that "if this goes into protected mode we lose all sound" was simply the amp for the stage monitors. The wires are all bundled up enough that is was not obvious where things went.

I think all I did was re-assign a bank to the Main L-R output, but I am not sure. I was walking through some of the let's make some sound work sections of the manual and I think I just double tapped the Main outs and the whole thing started working. The Solo issue stopped happening and it all started making sense. I told the teacher is was just magic. I really wish I knew, because I know they will ask me to fix it the next time, but I am out of my area of knowledge and this mixer system isn't the beginner mixer to learn on.

[Crash]

Next time, hand them the manual.