Control/Dimming Strange DMX Pro problem

[rbalewski]

Here's one that has me totally stumped. I've been using QLC+ on a notebook and on my office PC. It runs into an Enttec DMX Pro box. Everything was working fine. But then, I decided to put QLC+ on one of the PCs up in the booth to avoid taking the notebook up there all the time. I installed the exact same version of QLC+ and serial drivers as on the notebook. The install went smoothly, QLC+ saw the DMX Pro and seemed to communicate with it (green light started flashing). BUT I got nothing from the lights.

Now here's where it gets strange. Somehow or other, the configuration or drivers or whatever apparently got confused in the DMX Pro because the box will no longer work on either of the two PCs it used to work on!!!???!!!

I tried multiple lights and multiple cables, so I can't imagine that to be the problem. I also tried the Enttec control software directly. It sees the DMX Pro, apparently communicates with it, but nothing gets to the lights. Same with Magic Q - sees it, appears to work, but nothing. I also tried re-flashing the firmware in the DMX Pro with no help.

So at this point, I'm baffled. Any thoughts on what might be going on here???

 

[Mac Hosehead]

After reading the description of the issue, one possibility is a hardware problem. There is usually a separate RS485 line driver chip that can fail. If this is the case, everything else will check out but no DMX will be output. I do not know your interface well enough to tell you the chip that it might be but manufacturers often use a socketed chip as it is easier to change if there is a failure.

 

[rbalewski]

After reading the description of the issue, one possibility is a hardware problem. There is usually a separate RS485 line driver chip that can fail. If this is the case, everything else will check out but no DMX will be output. I do not know your interface well enough to tell you the chip that it might be but manufacturers often use a socketed chip as it is easier to change if there is a failure.

Thanks Mac. It could be a hardware problem. Having it go out just as I was installing it on another PC with no changes on the DMX side seemed like quite a coincidence, though. The unit apparently uses an FTDI USB-serial chip. Unfortunately, nothing is socketed. I wish I had a scope to see what, if anything,is actually coming out of the device.

 

[porkchop]

Thanks Mac. It could be a hardware problem. Having it go out just as I was installing it on another PC with no changes on the DMX side seemed like quite a coincidence, though. The unit apparently uses an FTDI USB-serial chip. Unfortunately, nothing is socketed. I wish I had a scope to see what, if anything,is actually coming out of the device.

If you have some kind of LED fixture that lights up when powered on with no data (fairly common) you could use that to test. If the fixture is still lit up in no data mode after the DMX dongle is plugged into it then you'd know the dongle is not outputting anything. If the light goes out then you know the dongle is outputting some kind of DMX even if it's not the values you're trying to send.

If you have a DMX test device other than this dongle I'd make sure that everything downstream is still working. It's unlikely that installing software would cause damage to your data system, but it's always possible someone unplugged something accidentally and you've been chasing the wrong problem. I wouldn't recommend it if I hadn't done it myself... more than twice.

 

[rbalewski]

If you have some kind of LED fixture that lights up when powered on with no data (fairly common) you could use that to test. If the fixture is still lit up in no data mode after the DMX dongle is plugged into it then you'd know the dongle is not outputting anything. If the light goes out then you know the dongle is outputting some kind of DMX even if it's not the values you're trying to send.

If you have a DMX test device other than this dongle I'd make sure that everything downstream is still working. It's unlikely that installing software would cause damage to your data system, but it's always possible someone unplugged something accidentally and you've been chasing the wrong problem. I wouldn't recommend it if I hadn't done it myself... more than twice.

Ours don't do that, but they do put out DMX, which is how I was able to test fixtures and cables.

I've simplified it down to one known good cable coming off the DMX Pro and going to one known good light and still nothing. I guess it was just a really strange coincidence that it chose that particular moment to die. I can't imagine a software install doing that, either, which is why I was convinced that it just messed up some kind of setting somewhere.