3 to 4 lights on one fader?

[andrewg112]

Hello,

Sorry to be posting so much at the moment, been really busy!

 

I have been sorting out a lighting rig, which consists of 3 ageing dimmer packs and a old lighting rig. Today after having replacing no less than 13 fuses, I had more or less a working rig.

 

The problem is that, im not used to Analogue dimmer packs, and dont quite understand them. Since moving the lights around I expected to have everything totally different, but the trouble is I have sometimes up to 4 lights on one fader and each light is individually plugged into a "channel" in the dimmer packs. I Just dont have a clue how to solve or begin to understand this!

 

If anyone has any ideas or late night reading, I would be grateful!

 

Thanks,

Andy

[Ynot]

It would help us to help you if you told us exactly what the dimmer packs are and what desk you have.

Photos if you don't know exactly what they are.

[andrewg112]

I did have a quick look on Google images, but couldn't find anything. They are older, possibly Zero88, although not entirely sure!

The board is a Sirius 24

 

Thanks,

Andy

[Tom Baldwin]

Assuming I read your post right, and there's no cross connection on the mains side (e.g. three sockets in the roof presented on one plug at the dimmers), most likely is either shorts in the analogue wiring, or potentially a missing ground connection.

Try moving your desk to next to the dimmers, and use a known good (i.e. all pins connected, no shorts etc) control cable to link them.

 

Can you give more specific examples - for example if lights 1, 2 and 3 come up when you raise fader 1, is this also true for faders 2 and 3? If not, what do these faders do?

Some dimmers (many) have test switches on the front panel - what happens if you use those? Does the problem persist?

What happens if you bypass the dimmers altogether, and connect one of the plugs coming from the lighting grid directly to a mains supply?

[andrewg112]

Okay, will have a look when I go in tomorrow. I guess I hoped I was just not realizing something big!

 

What do you mean by the term "shorts"? The cables are all connected through junction boxes to various points around the room. I could use one of them to see if it makes any difference.

 

Im far off with giving specific examples, im not in front of the board, or anything. Before my big move around today, it was only a few lights doing it, now its about 4 in a row at the back, which when they are all gelled different colors, is quite frustrating!

 

Cheers,

Andy

[Grahame]

, it was only a few lights doing it, now its about 4 in a row at the back

Andrew, we really need a bit more information from you as it's hard to tell what the set-up is from your posts.

 

It sounds like the lights in question are located at a distance from the racks in the hall somewhere - is that correct? If so, the most probably explanation is that

there are some socket pairings in the hall circuiting somewhere that is causing the problem. You would need to spend time plugging something into each socket in turn with only one fader up on the desk at a time to work out which fader is controlling what socket. If one fader is controlling more than one socket, then the sockets are probably paired. If more than one fader is controlling the same socket, then you have a fault somewhere.

 

Do the dimmer packs have outlet sockets on the front that then have a mass of circuit leads plugged in, or are the dimmers hard-wired into the rig? If they have sockets on the front and/or channel test buttons, check each dimmer in turn using a test lantern at the dimmer. If possible move the desk beside the dimmer and connect it using a short lead. Try to make things as simple as possible to isolate any problems; then add other bits of the system one at a time until the problem shows up.

[paulears]

It might mean a bit of running about, or a friend too help and shout - but pull the plugs out of the dimmers, have in your hand a know working light and shove fader 1 up on the desk, and then plug it into each spocket one by one. Hopefully, one channel will come up, the others being off. Then drop ch 1 bring up 2 and repeat. This will let you know if the fault is the desk or dimmers - if all works fine, then pairing is the likely culprit - I don't know Sirius desks, but is it possible somebody has simply patched all the output channels to the same fader? I have no idea if it's possible - but softpatching in controls often makes weird things like this happen?

[Just Some Bloke]

The cables are all connected through junction boxes to various points around the room.

 

That sounds like the biggest clue to me.

 

Turn the power off and take a look inside a junction box. If there are more cables going out to the lighting bars from the junction box than there are cables coming in to the junction box from the dimmers, then your sockets are imtentionally paired as part of the install. This is a way of keeping the cost of dimmers down whilst still providing plenty of outlets around the hall. Thus on your FOH bar you may have, for example, 12 sockets to plug your lights into but they may only use 6 channels of dimmer by pairing the 2 outside ones onto the same channel, then the next 2 in paired and so on. If at some point someone has come along and put Grelcos (or other splitters) onto each of those then you could easily end up with 4 lanterns on the same channel. That's Ok if theyre 500w lanterns and it's a 2000w dimmer, but if the lanterns are a higher wattage or the dimmer a lower wattage then you're going to have problems, and that ould be why the fuses blew in the first place.

 

P.S. Just another quick thought: in case t hat's not what's happening (or only a part of it) have a look in the menu of your lighting board and see if there is a command for "patch 1:1". If there is, then say yes to that command and that will ensure the board itself isn't causing the problem.

[andrewg112]

I think Eric just hit the nail on the head!

There are 4 bars and 3 dimmer packs. I believe there to be 8 sockets on each bar, so it could make sense this could be happening!

 

Can I ask where to find Grelcos or the Splitters, will they be up on the bar, on the board or in the control room!? I will also have a look on the lighting board for the possible patching issues!

 

Thanks for your responses, they are really helping me!

 

Andy,

[Ynot]

To answer your last question, grelcos/splitters can be anywhere on the mains side (usually the round pin 15A type) which can be where the end sockets are or even where the dimmers are IF you have plug-in type dimmers.

 

However, to sort out your overall issues you need to follow the suggestions already made - but I'll add one caveat - get yourself a big sheet of paper - A3 will do.

 

Draw a big box first - that's your hall/theatre/space.

 

Draw in all your bars, and note where all the sockets are.

 

If you have any other sockets (eg dips) at stage/floor level, mark them as well.

 

Now, check at ALL places where you can plug things in, and remove any greclos/splitters you can find.

 

Then plug a lantern in to as many sockets as you have lanterns, starting, for example, with a single bar - so if you have 8 ccts per bar, plug one lantern into each socket.

 

Then at your desk, pull up each fader in turn, making note of what lanterns come on for which fader.

 

Then move on to the next bar, doing the same, keeping notes, ad then do any of the dips.

 

Once that's done, look at the way that the socket numbering compares to the control channels. If there's absolutely no logical order to what you've written, then there is likely to be some other patching elsewhere in the system.

 

Actually, before you do all the above, a simple thing to do will be to look at the dimmer packs - do they have sockets on the front, or are they hard-wired? If the latterm then there SHOULD be a logical pattern to how they're wired, but if the former, then this could well be your problem. In that case you maybe need to pull all the cables from the dimmers and following a similar exercise to the first sugestion above simply identify what cable/plug feeds which socket on the bars. Then it's just a simple case of plugging these into whatever dimmer channels you need to use for whatever show you do.

 

But at the end of the day you MUST have a clear printed plan of how your circuit distribution is laid out/patched ASAP, else you'll continue to struggle in the future.

 

By the way - to assist in identifying the dimmer racks, browse these links for pics of the common makes.

Zero 88 Betapacks

Strand Tempus

Strand Act 6

Strand Mini 2

LOADS of others, though I suspect you may have one of the above.

[boatman]

Just to add to Ynot's post, and so that you know what you are looking for, a Grelco is a 15A round pin two way adaptor. There are a few different types around, but the most common one looks like this:

 

http://www.10outof10.co.uk/acatalog/grelco.jpg

[andrewg112]

Okay well,

There are no Grelcos on the Grid, or in any other outlets. One plug per switch. There are only two in the dimmer packs, and even then these are only 2 - 3 way ones with 2 plugs max in them.

 

I believe the dimmer packs to be ECS, this is the closest possible one I have found. The dimmer packs have no logos just a sticker with a model number (the sticker being identical to the one on the photos)

 

Cheers,

Andy

[timsabre]

It would be worth doing a factory reset on the Sirius 24, as I have known them to spontaneously repatch channels, causing pairing on channels and missing channels.

 

I would ring Zero 88, their tech support is very good and they will talk you through it.

[vinntec]

Andy - are the Sirius and dimmers directly connected by analogue cables or are they using DMX via a DeMUX? If analogue, then patching is a red herring as only DMX can be patched on the Sirius (and only if you have the DMX board fitted which sounds unlikely if this is an ancient installation).

 

A simple installation usually (but not always because that would be too easy) has a patch panel of some description somewhere if there are more sockets than dimmers - usually by the dimmers. One one side will be cables from each socket on the rig, and on the other 1-2 cables/sockets for each dimmer. If this is a school, this might be hidden from pupil view and forgotten about if not used for a while?

 

Second possibility is that the dimmers terminate as sockets on the wall and the bar cables (which might be Socapex or something else) plug in to these (so are patched at this point). These might be high up and in a and effectively permanently connected if no-one usually gets to them.

 

Third possibiity is that the dimmers are hard-wired to sockets on bars with some element of pairing built in (this would be totally daft but not impossible).

 

After that I am out of ideas for the time being...

 

Peter Vincent, Lighting Manager Chesil Theatre (Sirius 24 analogue desk)

[Ynot]

Third possibiity is that the dimmers are hard-wired to sockets on bars with some element of pairing built in (this would be totally daft but not impossible).

Sorry, but FAR from being daft, it's actually quite common.

In the right circumstances this is a pretty logical use of circuits.

Not ideal in a flexible rig, but nonetheless not rare by a long chalk.