[QLab] Help With Lighting?

[BareStage Theatre]

Hi Jim, Chris, etc.--
Update on the lighting problem:
We received the terminator and installed on last dimmer pack (there are
three) to no effect.
We have tried running only one dimmer pack with the board, and removing all
but a couple of lights and the flickers still happen.
We tried plugging dimmers into different circuits, but still get flickers.
We have switched out midi cables (both ones that came with the MidiSport
2x2) and the flickers continue. Could the cables be inferior?
Tried moving cables away from all boards, etc. to perhaps reduce
interference ‹ no luck.
For what it¹s worth, we can hear an audible buzz in the air when we cue
lights from the mac, but perhaps I just never noticed that before. Getting
hypersensitive to every click and buzz ‹ haha.
Also, we are running an older mac (the gumdrop iMac from around 1999, I
think), which does not have usb 2, could this not be supplying enough power
or speed? Should we tried to find a firewire interface?
Could the MidiSport be faulty? Would network hardware (wired or wireless?
Router? Airport?) interfere?
Outside of switching on the midi on the Behringer board, is there some
setting I¹m missing?
Ran MIDIMonitor and not sure what I¹m looking for, but every line said
³Element Command (coarse)² -- does that mean anything significant? It seems
to send 128 different commands to raise lights from 0 to 127 ‹ lots of room
for errors in that many commands, I suppose.
Next step is probably to try to run Qlab from a laptop and see if the same
problems persist.
My gosh, it would simplify everything so much if we could get this thing
working.
Any more ideas, anyone?
--Bryon




On Apr 25, 2007, at 1:08 PM, Jim Carroll wrote:

> Looks like this went to the list. The reply-to address is the list email, not
> yours, so I think do did it correctly. 
> 
> Line voltage is the power from the utility at the outlet. If you don't have
> good power, you'll run into problems.
> 
> I ran a children's theatre production in the local Grange Hall. They had 78
> volts coming out of one outlet and 104 from another. This meant that full
> power couldn't be achieved - kinda like having a dimmer set at 65% all the
> time. Light bulbs don't care - they just get less bright. Motors care - they
> get hot and burn up (brown out conditions) and Dimmer Packs need full voltage
> to process the control signals through their circuit boards. When the voltage
> gets low, some of the circuits will misbehave. Certain functions are voltage
> controlled -Simplified version of the logic:  [if voltage = 60, allow this
> operation to happen, if voltage = 120, do this instead]. If you can't get to
> 120, you can never get the 2nd option to function. The control board usually
> runs on lower DC voltage but has the same issues - 65% still isn't enough to
> get the response required from the board.
> 
> A volt meter in the outlet will tell you if there is a problem. I spent hours
> replacing control cable at the Grange Hall and then it clicked - one poke with
> the meter and we found the problem. Turned out after 3 sub-panels, we found
> one of the circuit breaker screws was loose on a wire. We cranked it down and
> everything worked perfectly.
> 
> Tripping breakers means you're pulling the maximum amperage from the system.
> If you hit a circuit hard in a short period of time, you can cause a voltage
> drop or surge (i.e. the lights dim for a second when the fridge or sump pump
> cycles). Again, simplified electrical theory: Electrical inefficiencies
> produce heat. Higher amperage means more heat is generated. Heat makes
> electrical circuits less efficient, which draws more current and boom- you've
> tripped a breaker. When you run close to the max, this cycle can be what
> causes the trips, but it shouldn't be the cause of the flickers. If you think
> back, I bet that you could run full lights for a period of time and then the
> breaker would pop, which meant things heated up.
> 
> Overall, it sounds like the line voltage is OK, but it is worth checking. I've
> seen discussions on the Theatre-Sound list about voltage conditioners from
> people who live-and-breathe electronics. Most were of the opinion that cheap
> voltage regulators are worthless. Expensive ones are _expensive_.
>  
> 
> Thoughts on troubleshooting after checking the power: I would try removing the
> dimmer packs and adding them one at a time to see if the problem is always
> present with QLab or only if a certain load is met.  Do you have another MIDI
> cable to try? If I recall correctly, you already tried varying the command to
> different levels and across different amounts of time. After that, I'm
> stumped. Good luck!
> 
> Jim

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