DMX pass thru

[hoffmana1]

the dmx on our batten isn't working when the pass thru button is in or out but it does work when we hold down the button, has anyone else had similer problems and what do you think is wrong?

 

[BillConnerFASTC]

Sounds like the (button) switch has failed. Why would you think otherwise? Any clue as to vintage of this part of the system?

 

[DavidNorth]

Please do include facility info or a pic. Are these pushbuttons that have a green indicator built into them? If so, it might be an ETC strip, and yes, could be a bad button. Do you have others that are working?

Let us know,

David

 

[hoffmana1]

They are all etc and they only don't work on the electrics

 

[greatpopcorn]

To give a little more information (I work in the same theatre) the Pass-Thru functionality is supposed to work as a temporary output, and if it isn't needed, you "Pass-Thru" it and it goes straight to the other output on the electric. The other output on the electric works only when you hold it down all the way from being engaged. Otherwise, the DMX disconnects. All of the electrics (4) exhibit this same behavior of only working when the button is held down. See the attached drawings for more info.

 

[RickR]

The drawings have a 2008 date. I wouldn't think the buttons would wear out so soon but they may be past warranty.

Regardless, calling ETC tech support is your best bet, and you're over half way there with @DavidNorth on the line. Those drawings also have your job number, with that they will pull up virtually everything ever known about your system.

 

[greatpopcorn]

We figured that, just wanted to make sure we somehow were using the Pass-Thru incorrectly.

 

[Thetechmanmac]

Have you tried just using a DMX cable from the output to the input? That would essentially have the same effect as the pass through switch.

 

[greatpopcorn]

We don't have that much DMX on hand at the moment, but we are trying to borrow some from our school's tech department.

 

[Thetechmanmac]

Give that a try. then you will know for sure if it is indeed the switch.

Another question- Is this happening on all of your DMX pass throughs, or just one?

 

[greatpopcorn]

All. It's the weirdest thing, like maybe we got a bad batch? NOBODY at the theatre has ever touched these before.

 

[Thetechmanmac]

Hmmmm. I wonder if its maybe a bad cable at the start of the chain. I have never been around ETC distribution with DMX on the electric. Most of them Im around are only circuits.

How many electrics do you have and how many pass through switches?

 

[greatpopcorn]

According to the drawings (interpreted by someone at ETC) the electrics SHOULDN'T be hooked together. The Pass Thru is only for that electric specifically. So I would find it characteristically odd that 5 independent cable runs back to our dimmer room (verified that they are independent lines) are all bad. Plus the light wouldn't work when the button was held down. -_-

 

[greatpopcorn]

Anyways, a call to ETC support should probably clear up this issue, or at least tell us that we can't use DMX in our electrics. Either way, its better than our current worst scenario option, which is to gaff tape the button down.

Gaff tape solves almost every problem in our theatre. It's pretty much the equivalent of duct tape at this point.

 

[DavidNorth]

So when the indicator is off, the button should be out and the DMX Out should be active with data. Then, to get DMX down the rest of the distro strip, you have to put DMX back into the Input. The concept is:

DMX Output ---> DMX device on pipe ---> DMX Input

Now, when the indicator is on, the button should be in and there is no data available on the DMX Out connector. This allows DMX to keep going down the strip without interruption.

This design was done in order to prevent DMX Ys on the output down a strip. So while it seems a little unusual, it serves a very good purpose. Each distro strip should be on its own separate optosplitter output. FYI, the indicator is mechanical in the switch and is not a light or LED.

So what you are saying is that you are only able to get DMX Out from the plate when the switch is pressed in and held, and you are not able to get DMX from the Out in either switch location?

I have this strange feeling that I've seen this before. IIRC, I think the wiring on the plates inside the strip is backwards. My guess is that if all the switches are in the Pass Thru [indicator visible] position, then DMX would be active on each of the DMX Input connectors. Do you have a 5-pin turnaround that you can use to check this? I'm about 95% sure this is the issue.

Let us know,

David

 

[Thetechmanmac]

Either what David said or you could have a problem with your opto splitter, or the line feeding it

 

[BillConnerFASTC]

So with button out, a patch cord from out to in, should be same as button in, correct?

 

[DavidNorth]

So with button out, a patch cord from out to in, should be same as button in, correct?

Yes, that's correct.

 

[greatpopcorn]

Ok, so the output on the other end of the connector strips doesn't work in EITHER position of the switch, but when you depress the switch all the way in from green (Pass-Thru ON), the DMX output on the end works as long as the button is held. From looking at the diagrams, the only thing that would make sense is if the output is in fact patched as the input and vice versa, and this button press shorts all three of these connectors (input, output, and the other output down the line) together and creates the signal on the third. @DavidNorth, is that what you were saying? And, is this something we can fix ourselves if that is the issue by placing a patch cable between the two lines and testing the third?

Thanks for all your help. We have had this problem for about 6 months and we finally have about a week of dark or one day shows so we can try and fix this.

 

[BillConnerFASTC]

Does anyone know if it has ever worked as intended? First year?