Zero88 Jester / Showtec Multidim MKII Strange Behaviour

[ItsMyNaturalColour]

Hey everyone,

 

I'm having major issues with a rig that I operate from time to time.

 

To cut a long story short, an installation was taking place (of some lovely new moving heads in the same building), so at the same time I got one of the installation guys to make me up a short 5 pin to 3 pin DMX cable. I wanted this so that I could connect a standard Zero88 Jester 24/48 directly to a Showtec Multidim MKII dimmer. The same Jester is being used with some LED Pars and some conventional lights on the same rig.

 

So, this was the old setup:

Jester > LED Cans x12 > Existing Dimmers

 

This is the new setup that I'm trying to get working:

Jester > Showtec Multidim > LED Cans x12 > Existing Dimmers

 

This rig is a little bit 'all over the place' because the LED cans are grouped strangely (somehow) with lots of patching changes in the Jester. The original dimmers are analogue, so there's a DMX to analogue converter hanging around somewhere in the chain too, adding more confusion.

 

This is the problem. When I switch on the Multidim, all 4 channels are at 100% constantly. No matter what I do on the desk (even pressing the blackout button) doesn't resolve the issue. The only way to stop the 100% output on all 4 channels is to completely turn off the dimmer. The other interesting thing is, the rest of the rig works just as it did, absolutely fine. I'm pulling my hair out trying to figure out what the hell is wrong with it.

 

The dimmer works fine. I connected it to a simple DJ style DMX controller that was hanging around and it behaved wonderfully.

 

I've also flicked through every single DMX address on the dimmer, and across the entire range the output of all 4 channels remains at 100%. All settings on the dimmer are fine. I assume the 5 to 3 pin cable is fine, but I've ordered another just incase it's not. However, I assume it's fine because the rest of the rig (now running through the Multidim) works fine?

 

I can't move the location of the dimmer in the chain because the 4 IEC cables are running into the control room, where as the LED cans are at FOH, so there's long cable runs in the celling and what not. The reason the IEC cables are coming into the control room is because they were used as a separate rig with 4 x PAR64 cans with one of those "controller dimmer" type things, 4 faders and some dimmers in a box. All I'm trying to do is incorporate those PAR64's into the same rig, controlling them from the Jester. This is why I'm trying to add the Showtec Multidim MKII.

 

Any suggestions?

 

Thanks so much once again,

 

Tom

[timsabre]

So if you turn on the dimmer with no DMX, are all channels off? Then when you plug in the DMX, all channels come on full?

It sounds like your new adaptor cable is wired incorrectly.

 

I don't quite understand how you have gone from your old setup to your new setup with the addition of a single 5 pin to 3 pin adaptor.

[ItsMyNaturalColour]

Yep that's right, dimmer itself is fine. As soon as you connect DMX, all 4 channels hit 100%, but only with the Jester.

 

Basically, a 5 pin DMX cable was originally connected to the Jester. He chopped off the end, wired in a 3 pin DMX plug, connected that to the DMX Out of the multidim, and wired up a new 5 pin to 3 pin cable to go from the DMX out on the Jester to the DMX in on the Multidim.

 

Thanks,

 

Tom

[alistermorton]

If it's one of the clone 4 way dimmers also sold by skytec, transcencion etc we had one and discovered that the DMX polarity to the board was reversed - if you check the screen printing it may even reveal that. Lifting the connector from the XLR to the PCB and reversing it made it work perfectly - it's a 3-pin connector that can just be reversed.

[mac500]

Are you sure your not outputting a cue on the jester with everything full.

[ItsMyNaturalColour]

If it's one of the clone 4 way dimmers also sold by skytec, transcencion etc we had one and discovered that the DMX polarity to the board was reversed - if you check the screen printing it may even reveal that. Lifting the connector from the XLR to the PCB and reversing it made it work perfectly - it's a 3-pin connector that can just be reversed.

 

That's really interesting. It's a Showtec unit but I think they're all pretty much the same. I've got a spare DMX phase reverse cable, should I try this? Funny thing is, the rest of the lighting still works as normal, even running DMX through the dimmer, so it's strange how it's just the dimmer acting up.

 

Are you sure your not outputting a cue on the jester with everything full.

 

100% sure. As I say, the rest of the stuff works great, it's just the Showtec dimmer behaving in this way. Also, blackout or grand master at zero doesn't change anything. All 4 channels still remain at 100% intensity.

[timsabre]

That's really interesting. It's a Showtec unit but I think they're all pretty much the same. I've got a spare DMX phase reverse cable, should I try this? Funny thing is, the rest of the lighting still works as normal, even running DMX through the dimmer, so it's strange how it's just the dimmer acting up.

 

Yes, but if he wired both ends the same way, this is what would happen. You will need 2 phase reverse cables to fix it, but you can test the dimmer on its own by plugging the reverser into the input of the dimmer.

[ItsMyNaturalColour]

Right, I think he may have done that. I'll source 2 phase reverse cables to give it a go. It would be great if this fixes the problem, I'd then just use another 5 pin to 3 pin cable, and stick with phase reverse on the output.

 

Just to clarify, if he's wired the 3 pin connector on the output of the dimmer incorrectly, shouldn't that impact the usability of the LED cans connected next? The LED cans are working absolutely normally.

[timsabre]

Right, I think he may have done that. I'll source 2 phase reverse cables to give it a go. It would be great if this fixes the problem, I'd then just use another 5 pin to 3 pin cable, and stick with phase reverse on the output.

 

Just to clarify, if he's wired the 3 pin connector on the output of the dimmer incorrectly, shouldn't that impact the usability of the LED cans connected next? The LED cans are working absolutely normally.

 

Your guy has wired up two 3-pin connectors, 2 things may have happened

 

1-the dimmer itself is wired backwards. This means that it will pass the DMX through correctly, but won't understand it itself.

2-both 3 pin connectors have been wired backwards. This will reverse the data into the dimmer, but then reverse it again on the output, giving a correct signal to the rest of the line but inverted to the dimmer.

[ItsMyNaturalColour]

Right, I think he may have done that. I'll source 2 phase reverse cables to give it a go. It would be great if this fixes the problem, I'd then just use another 5 pin to 3 pin cable, and stick with phase reverse on the output.

 

Just to clarify, if he's wired the 3 pin connector on the output of the dimmer incorrectly, shouldn't that impact the usability of the LED cans connected next? The LED cans are working absolutely normally.

 

Your guy has wired up two 3-pin connectors, 2 things may have happened

 

1-the dimmer itself is wired backwards. This means that it will pass the DMX through correctly, but won't understand it itself.

2-both 3 pin connectors have been wired backwards. This will reverse the data into the dimmer, but then reverse it again on the output, giving a correct signal to the rest of the line but inverted to the dimmer.

 

Right, I totally get you 100%.

 

Thanks so much for this. Soonest I can get in to test is Monday, so I'll report back. Luckily I've got 2 x 3 pin phase reverse cables that I use with my old Martin 812 scanners, so I'll throw these on both the input and output to see if that works.

 

Like I say, I'll report back as soon as I'm back on Monday. I'll lock the windows and swallow the keys just incase I get tempted to launch the dimmer or desk straight out into the wild.

 

Huge thanks,

 

Tom

[ItsMyNaturalColour]

Thanks so much for your help everyone!

 

I stuck a phase reverse adaptor on the input and output, and it works a treat. Absolutely lovely. Chuffed to bits. The only one remaining slight annoyance is the difference in dimming curves between the existing dimmers and the Showtec unit, but, can't be helped. It's still a good piece of kit for the price.

 

Thanks again everyone, sorted!

 

Tom

[alistermorton]

Does sound like the same problem we had - the screen printing on the front panel of the unit matched the way the connector was wired to the board, which was like an old Martin unit with the hot and cold reversed compared to normal.

 

As I say, we just reversed the connector and taped over the incorrect screen printing. The dimmer now matches all our other 3-pin DMX stuff.

 

http://interactive-online.com/support/knowledgebase/42-DMX-512/117-DMX-512-connector-pinouts