Help! Mac 250 Entour Acting Up

[DRG]

I've got a problem with a Martin 250 Entour. Sometimes I lose control of the unit entirely, it will start strobing, gobo scrolling etc (almost like it had a sound to light function) and there's nothing I can do to control the unit individually. Even reset doesn't work unless I select the whole group of Entours (16 total) and then reset them all (I'm using Hog 2 PC). No error messages display on the unit when the problems occur.

The unit is 4 from the end of a chain. The 3 after show no problems, nor does anything before it. The DMX chain is terminated. I even changed the terminator, still no luck.

The address is correct on the unit, nor does it conflict with anything else on that DMX universe (universe 2 of 4).

The only odd thing I can see is that when I remove the "data in" cable the DMX light remains lit, and only goes out when I also remove "data out!(?)"

I swapped the unit with another one, and the new unit has exactly the same trouble, and the old unit works perfectly elsewhere, so I can rule out hardware issues(?).

The power is through a series of non-dims, so I tried changing the power source, the problem remains.

I'm using properly rated DMX cable, but I swapped the one going to data in, again the problems remain.

 

I've emailed Martin support, but well, it's Saturday.

 

Any help at this point would be greatly appreciated.

[johnhuson]

What happens if you unplug the fixtures downstream (connected to the DMX Out) of the fixture showing the problem? Sounds to me like it could be a problem with a fixture or cabling down the chain from the one showing the fault.

[Ynot]

You do have the right personality set on the fixture, yes?

IIRC, they're 15 or 18 channels (standard and extended) - maybe the rogue unit is set wrong....

(There's also an outside possibility that desk profile may be set wrong on that unit, too.....)

[Tomo]

The only odd thing I can see is that when I remove the "data in" cable the DMX light remains lit, and only goes out when I also remove "data out!(?)"

That's an important clue!

What you've said implies that something downstream of the fixture is the cause of the fault - what happens if you only disconnect the DMX-Out at the problem fixture, then try to control it?

 

Have you sketched out the *entire* DMX distribution system as it is actually installed? (Don't guess - check!)

 

This sounds like there is a passive Y-split in the DMX distribution, or that the DMX distribution is running backwards to what you expect - thus putting the terminator in a very strange place...

 

The Entours have both 3 and 5-pin connectors - make sure that you are *only* using two connectors in any one fixture - if you connect more than this, you have introduced a passive Y-split.

[hippocrocaphant]

You have ruled out the problem being with the fixture since you have swapped the unit out and had it working well elsewhere on the chain, therefore the problem has to be with the DMX line. Check every single cable on the line, I suspect the problem is after the problem fixture.

[zonino]

this is probably obvious after tomo's post, but unplug the DMX-In to the problem fixture, the work back from the end of the chain unplugging each fixture, and see when the DMX light goes out on the problem fixture, that should pinpoint the problem area

[DRG]

Thanks for all the assistance.

I did trace the DMX lines and actually found that there were a couple of passive Y-splits (courtesy of a lazy installation team), which were being connected for a once a week production show only. I removed them before my original post here, so this doesn't seem to be the issue.

The problem wouldn't replicate during testing today, but I replaced both the line of data after the problem fixture, and also the Entour after to see if this helps.

Hopefully everything will be ok come tonight's show!

Speaking of which, gotta go....