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I just bought an FC-400 DMX foot controller that I'm trying to program. When in programming mode, I can set channel 1 just fine. Most of the time, setting channel 2 also works OK. Things start to get all screwed up by channel 3 though. Changing the settings on channel 3 or 4 of any given scene alters the previous channels in that scene that I've already set up.

For example, if I set scene 1 channel 1 to show a red light and set channel 2 in that scene to blue, that usually works. If I start scrolling through colors on channel 3, the red & blue on channel 1 & 2 also change.

I'm doing this with 4 single-channel DMX color changers (no dimming), each set to different channels - 1, 2, 3 & 4. I'm assuming that since this controller is only a 4 channel DMX controller that the only channels available are DMX channels 1, 2, 3 & 4. Is that right? And if I'm reading the manual right, I should be able to set up 12 scenes of my own using the FC400. I have no plans to use chases, just static scenes with no moving heads or anything like that. Just using color changers, used like pars that can change colors. We're a blues rock trio and don't need a lot of blinkyflashy, but want more than a couple washes set to auto-stupid. ;D

All cables used are DMX specific without a ground connection to the barrel of the XLR plugs to prevent ground loops in accordance with the DMX standard. I'm also using a terminator, even though I'm only using 4 fixtures and total cable length is only about 50 feet. I've also tried switching the DMX polarity both ways and that's not the problem.

Is there something wrong with my FC400 controller? Obviously I'm not doing anything stupid like powering my DMX color changers on dimmers or anything like that. Everything has plenty of AC power, but as it is I can't get any programs set up to actually use it.

Any help is appreciated.

Cheers,
- JJ
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JJ,
The FC-400 was designed to be used with a 4 channel dimmer pack. For that reason the controller only displays the percentage output (0-100% or 0-FF) and not value (0-255).

As for programming scenes, the 4 channels do not affect the output of one another and work completely independent.

What model fixtures are you trying to control? There's a possibility that your fixtures use more than one channel of dmx and that's why this is happening.
Hi - thanks for the response -

I left the unit plugged in over night and switched the DMX polarity (again) and it seems to be working. It's an LSC unit dated 2003 with an ADJ warrantee card in the package. It was new (still sealed in plastic), just never opened and sitting on shelf for the last 5 years.

I'll leave it unplugged for a few days and see if that contributes to the problem. Do these have an internal battery or do they write to an EEPROM every time it's reprogrammed? I don't want to void the warrantee by opening it up just to look inside.

The color changers I have (MBT) respond to either 0-100 or 1-255 like most any DMX fixture. Of course I have to do a little math to find which 0-100 number corresponds to 1-255. Dimmers translate DMX just like any other fixture from what I understand reading the USITT DMX standard.

Another thing I think may have been contributing to my issue was that it was stored so long that the polarity switch could have become corroded a little bit. Not much, but just enough that it took a couple times turning it back & forth to clean the contacts in the switch. I'll probably hit it with some DeOxIt as well as all the footswitches while I have it sitting for the next couple days to see if the EEPROM (or battery) inside leaks down.

Cheers,
- JJ
Last edited by Former Member
Hi,
I haven't used it for a couple days and plan on using it this weekend. I got it working by running the DMX polarity switch back & forth a few times so I think it was just a little corroded from age. I'll check it out tomorrow again and if it still has all the scenes I programmed in it, I'd call it fixed. ;D

Cheers,
- JJ
Well, I just hooked everything up one more time and ran through the scenes I programmed in last weekend. I had everything put away in their cases so nothing was left plugged in to hold a charge or anything.

Everything works as it should. I suspect the DMX polarity switch was just a little gunked up from storage (about 5 years) and needed to be slid back & forth a few times to freshen it up. I can see how having bad electrical connections in the DMX signal path could result in random firing of the signal giving weird results on the fixture end of things.

Everything's cool now!

Thanks

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