leap frog & DMX issue

[eamon]

Hi all

 

I am looking for some advice and possible answer to a query I have with regard to DMX flickering issue.

 

My normal set up is 4no. Rjuliat Tivoli Dimmers linked via a daisy chain into the patch panel & then into the house buffer. This has been the way for 12-13 year's. My main control is an ETC Ion/520i and I have had numerous different desks of many different sizes in control over the years. All my cable is "proper" DMX cable etc.

 

I have a musical in & running with a Leap Frog controlling the show. My dimmers are having very random pulses and dropping out of lights over stage. The problem is pretty much confined to Rack 3 (49-72) & Rack 4 (73-96). Not all dimmers are in use and there are no movers etc just generics. This action happens randomly with out input from the op.

 

As of now, I have ran each dimmer direct into the buffer with new 5pin Sommer DMX cable (quite nice stuff btw!). I have replaced all the DMX cable within the previous set up.

 

My question is do people reckon it could be the desk or the dimmers? My gut says desk and I have a feeling it is spitting out bad DMX. This is a feeling without any hard evidence.I have never encountered this problem before with my set up hence my thinking it is the desk. It is the only big change since the last show.

 

Rack 3 crashed prior to the dress rehearsal and took a lot of persuasion to come back to normal working mode. It had defaulted to dim 1-24 and would not take a new start address. I replaced the batteries in the units approx 18 months ago.

 

I am just looking for feedback and advice from those that would be familiar with the leap frog series etc. My true knowledge of the zero 88 range stopped with the sirius 24 (great desk!). They are just not that common in Ireland within the theatre market.

 

My belief is that is the desk. I am unable to get the software version it is running till end of the matinee. Is there a way to adjust the refresh rate of the console DMX?

 

many thanks in advance.

 

 

eamon

[s buckley-jones]

? why do you think the desk is the source of the problem . global DMX to all racks would give fault on all racks not just 1 or two racks .

have you tried re patching the DMX inputs to the racks . does the fault move

if you can strip the buffer out that will remove it is as a source of a pos problem .

best guess A buffer . B rack .. C cable or termination.

 

 

just cause you put a new battery in 18 months ago does not men it is still good . there are a lot out there that are just not what they say on the box and do not last.

[Brian]

On that desk, do you have the option of slowing down the DMX refresh rate?

[niclights]

In my experience random flashes or dips are caused by DMX timing issues. I have always solved with other consoles by enabling an extra stop bit. If the Z88 has this option there's not much to lose by trying. Similarly, adding terminators is easy and won't hurt. Could be lots of other things though. There's no substitution to a systematic investigation but if it's intermittent obviously that's going to be easier said than done.

[vinntec]

Hello again Eamon - when you say Leapfrog do you mean the original Frog series one or the newer Leapfrog 48 or 96?

 

If old, on our Fat Frog - shortly to be decommissioned as we have outgrown it fixture wise, we do get similar symptoms because one of the playback master faders (A I think) is dirty and needs to be absolutely at the top to stop the flickering. There is no way to adjust timing, but I have used these desks with a lot of different dimmer makes without problems both analogue via DEMUX or direct. You can reset the DMX output in Super User, but that's all. The original ones only had a single DMX output but later ones might have had two, if so it might be worth trying a repatch onto the other one?

 

This desk I have only investigated a few years ago but never used so more speculative:

If a Leapfrog 48 or 96, If you are using a single universe have you tried repatching onto one of the other DMX outputs (I think you have 4?) and see if the symptoms change or go away? The manual shows no way to adjust DMX timing as far as I can see.

 

General (just wild ideas):

Is this a venue you have run no problem at in the past with a different desk?

Are all the DMX strings from the buffer terminated?

Are you able to take the DMX buffer out and connect everything in a single DMX string with a terminator on the end?

Years ago at a school (with Sirius) we had random flickering and it turned out to be the power supply overloaded when the tea urn was turned on as it was on the same phase as the theatre lighting.

I believe you can get strange events when the phases are way out of balance, but need someone with more knowledge than me to comment on this possibility.

What rated power supply is supposed to be available for lighting? If you trace it back to the building supply can it really support it?

 

Peter

[eamon]

Hi all

 

Thanks for the responses.

 

I have placed each dimmer on its own line into the buffer. I did this at the interval. There has been no re-occurrence of the pulse yet. As above, I have used new cable to bypass what is there from the original install.

 

The OS on the desk is 7.7.0 if that makes any difference.

 

My reasoning for the desk being the culprit is to do with what has changed since the last show. My house dimmer layout has not changed till the interval as above. The company are using their desk which is the biggest change. Just following a fault finding in my head and knowing the system intimately etc. Have fault finded before and just following a hunch.

Will be checking all cable for dry joints etc.

 

The batteries were put in for another reason and was a recommendation from R.Juliat themselves. I am figuring this is not part of the problem but added it in for information purposes.

 

I thought of slowing the DMX refresh rate down on the desk but there does not appear to be that option in the set up. It could be there. The op is unaware of it and I am about to download the manual.

 

When it settles down next week, I will be opening all boxes and looking for possible faults. I have been on to Rjuliat for a separate issue that has come up with a heat test conducted a few weeks back. Might be best to get the (now new) local dealer out to give the racks the once over. Have been through them and so far all is in good working order.

 

 

 

cheers

 

eamon

 

Hi Peter

 

You posted as I was composing mine.

 

I believe it is one of the newer Leap Frog 24 way desks. It has 2 x DMX and a variety of other protocols accessible on the rear of the console. We are using Port 1. Did not think to swap ports. Kinda obvious when I think of it...

 

I am resident in the venue and look after all parts of the operations. We have placed numerous consoles in charge of lighting from small manual to Hog etc.

There is no termination in place and that may be a reason why the flicker is happening. Again this supports my suspicion it is the console...This is just a hunch.

Each rack is connected to the buffer on its own line. Will be popping over to maplins in a few mins...

13amp desk power is sourced via an RCBO from the dimmer supply. Plenty of power and clean at that. The building has a large capacity (400-500amps)and we are pulling a small rig in terms of load.

 

 

many thanks

 

eamon

[david.elsbury]

Sometimes with some desks or kit it will work fine with no termination. That's not to say that it shouldn't be terminated though.

 

Then you add kit or change desk. .. and problems arise. Worth adding a terminator to see what happens.

[jonhole]

Hi eamon,

 

The OS on the desk is 7.7.0 if that makes any difference.

Should be fine, but we have just released 7.8.0 which is recommended for all users, you can download it from http://www.zero88.com/software/zeros

 

I thought of slowing the DMX refresh rate down on the desk but there does not appear to be that option in the set up. It could be there.

Correct, there is no way of doing this currently. That said, our DMX output sits within the DMX specification, so there shouldn't be any problems.

 

It has 2 x DMX and a variety of other protocols accessible on the rear of the console. We are using Port 1. Did not think to swap ports. Kinda obvious when I think of it...

Are the LEDs by the DMX outputs green or orange? If you switch to the second output, you can patch the outputs in SETUP > Desk Setup > Outputs

 

we do get similar symptoms because one of the playback master faders (A I think) is dirty and needs to be absolutely at the top to stop the flickering.

If this was the case (or something similar) you would see this flickering in the Output Window too.

 

One way to see if there is a problem with the output would be to link the DMX Output and the DMX Input with a short DMX cable. You can then open the 'DMX Window' (in the Output window, select 'Other Windows' and then choose 'DMX Window') and then choose 'DMX In'. You'll see exactly what the desk is seeing on the DMX output, and you will see if anything changes (values highlight for a few seconds if there's been a recent change, so you'll still be able to tell even if it's too quick to notice)

 

Hope this helps, alternatively, give us a call tomorrow morning and we'll go through some further trouble shooting with you - 01633 833101