Sirius 500 and NJD IF-16 problem

[Robin D]

I was originally going to resurrect this thread as it seems closest to the problem I'm having and I wondered if the issue could be phase reversal or if anyone has other ideas? However, it doesn't fully describe the issues so decided to post a new topic. Apologies for going on a bit, but I'm trying to get all relevant information in the one post!

 

The rig: Zero 88 Sirius 500 desk (DMX output) driving three old (but sound) Berkeley Colortran 6-pack analogue dimmers using a NJD IF-16. (Two packs get 6 channel control, the third only the first 4). I was trying to use it to light four short shows over the weekend for a stage school and ended up using the original analogue two preset desk which was interesting when they wanted the lights to 'flash' during the songs! The kit is all my own and I do the shows gratis as its good for the kids to become used to working under lights.

 

I've not used the desk in anger as I've spent the last few months replacing faders etc after buying it in a sad state from a school. It's my first venture into DMX although I've rigged it elsewhere. The dimmers I've had for years and the IF-!6 I picked up somewhere along the line as a give away when buying lights from someone who was giving up.

 

The IF-16 has 1/4" jack DMX so I made a short link cable by replacing a XLR5 on one end of a working DMX cable and connecting as per the diagram on the case.

 

The issue I have is that the the channels that the desk is outputting are not driving the respective channels on the dimmers and many channels do nothing. (The desk has been reset to default with generics on 1 - 40(?) and the DMX patch cleared.)

 

I have no other DMX gear to hand, so am unable to easily determine if the issue is the desk or the demux. So to the questions:

1. Can I assume that the displayed DMX output on the desk is correct. Is the monitor reading back from the DMX section, or is it what it believes it's feeding into the DMX?
   
2. Is there a simple (and cheap :D ) way of determining if the DMX signal is good?
   
3. Are there known problems with NJD kit and phase reversal or would I do better to try to find a 'proper' demux? Setting it all up at home is 'challenging'!
   

Any thoughts or comments please?

 

Thanks ...... Robin

[KevinE]

Theses little boxes by NJD are pretty robust really and perfectly compatible with any other DMX

stuff.. It might be worth temporarily swapping hot and cold DMX lines just to make sure, you wont do any harm so long as the screen is always in the same place.

 

Dont forget the NJD needs a 15v DC auxilliary supply, normally back-fed from an NJD analogue dimmer pack..make sure the Berkleys can cope with this and the polarity is right. A quick search says that Berkley normally used 20V DC aux out.

 

Other than that you need to make sure the desk is ok..and the NJD is ok...by substitution if nothing else. But that's the obvious answer!

[Robin D]

Thanks for the rapid response Kevin.

 

I'll play with the DMX polarity and see where that gets me. :D

 

The packs deliver +17v and -17v according to the PCB and + & - 16.8v measured. That's well in tolerance for the 15v expected by the NJD. (The user guide states: Do not connect to a power packs with a supply voltage output of more than +20V ...). I guess there could potentially be a current problem but I'd discounted that with the size of the rail! The NJD only needs 100mA.

 

If not, I'll have to see what I can borrow from elsewhere to isolate the problem.

 

Many thanks again ........ Robin