Control/Dimming - 1982 ETC system Vs 2008 aug. Thunderstorm

[mattbarnes84]

OK to start this on off I'm the Tech at Tift Co. Comminty Theatre. It holds an old ETC system with a microvison FX console. The kicker of all this when we use any console (microvison, maxis, KLS) they dont work... But when i use my Cyber-contoler USB DMX everything works. ETC cant fix the problem were having. how can 3 other controler and the one thats made for it want work? but the the DMX on my PC will. were starting to have shows left and right this year. and i'm having to run lights, sound and fix it when it breakes... just to kick out other options when i use the microvison at home it runs my dimmers with no trouble? we replaced all the DMX wires and the addressing controler.

[DavidNorth]

Matthew,

I can understand your frustration about not getting this system back together so far. In looking at your contact to ETC there is no doubt that the system was hit by either lightning or suffered a catastrophic power cube failure. FYI, the system was installed in 1993 instead of 1982. Either way, I am hoping that the facility owner contacted their insurance company as this may be covered under their policy. This will also help pay for ongoing service as we dig through the breadth of issues since they encompass the control modules, architectural processor, architectural stations and control console.

The reason that the USB DMX device works is that its common is not tied to earth ground whereas it is on the MicroVision and likely so on the other consoles as well. This means that there is still a wiring or control problem or possibly wounded DMX reciever or transmitter chips in the system which need to be located.

Feel free to call us again or call me directly and also to continue to work with the tech working on the system last fall. Let me know how I can help.

dnorth (at) etcconnect (dot) com

David

[mattbarnes84]

sorry about the date of install i was looking at my paper notes on the building and that were i got the 1982. other than that thanks for the info and advise. i have ran all new DMX cable and i have a Elation DMX operator-pro on order. i have dropped the ground on our maxis console but still have no control. plus i want to give a big thanks to ETC for helping me with all the trouble iv ran into so far.

I still have the train-of-mind that if there was away to completely remove the controller, and the other electric controls away from the main power that supplies the ETC system would solve a lot of trouble. "Tifton's Power Grid is a broke Joke"

[dramatech]

I had a simiilar problem several times a few years ago, except that the system was an ETC Express 125 and an EDI MK7 rack. After having the EDI repair guy several times in less than a summer, I found that the problem was a ground loop in the theatre wiring that kept taking out the data transceiver in the rack. I did quite a few different things to solve the problem. It probably was just one of the things that I did, that solved the problem, but which one I'm not sure.
First, I installed the best surge protectors that I could find on all three phases of the control circuitry in the rack. Secondly, I installed a relay on the DMX input, so that the transceiver could not get an input signal unless the rack control circuits were powered. Thirdly, I ran power from the rack to an outlet for the control console to plug into. (eliminate long ground loops in the building), and last of all, I put and optoisolator between the console and the rack. I used an elation optospitter. One other thing that I did, but is probably not a problem that you would have, was to modify the input of the control circuitry boards. It seem that the early EDI MK7 racks were designed to accept quite a number of different input protocalls, and used a tranceiver chip designed for RS 422 and not for RS 485. Even though both are a balanced line tranceivers, and should accept each others standards, (this according to the EIA documents) I really wanted to eliminate any problems. Since performing all of these changes, a little over three years ago, we have not had any problems. (Loud knock on wood)

[mattbarnes84]

I'm trying to find all the wiring diagrams for our theatre. everything in the place looks older then me. David from ETC said it was all installed around 1993. iv been looking for bad wires. but nothing so far. as soon as i get the wiring diagrams ill know were every is to check.

[Sony]

ETC Will have a diagram on file for you if you cannot find one. ETC meticulously records and stores all the wiring done for every installation they have ever done. I'm sure if you ask David North he can get one for you, in fact I bet you he already has pulled it up so he can help you with your problems.

[mattbarnes84]

Yeah David is great he sent the install diagram today. it helps a lot to have something to look at other than a hand drawn system info... i love to have the building blue prints as well but i don't think the City will release them to me.

[Sony]

You most likely can't get the originals for obvious reasons but you can probably get copies from City Hall. No harm in asking at least.

[mattbarnes84]

thanks i'll try Friday to see if i can get anything.

[FMEng]

I think you are looking at the wrong end of the system. I've spent a few years maintaining electronic equipment attached to radio towers, which are basically giant lightning rods. Generally, the components closest to long cables wind up acting as fuses protecting everything else.

Anything is possible, but I would be very surprised if lightning damaged the DMX cabling. It is much more likely to damage electronic components first. I would concentrate on the DMX receiver components in the DIMMER rack. It obviously still functions to a limited degree, but a termination resistor, a pair of shunt resistors, or the chip may be fried enough to change the load to a value way off from the standard 120 ohms. Or, it could be half dead, making it un-balanced. That would make it hard for most devices to drive the input.

A possible reason that the USB device works is that it just happens to handle a mismatched or unbalanced load better than the consoles.

The nice thing about lightning damage is that it often leaves physical signs of damage, such as discolored components, burned traces, soot trails. If David can tell you where on the dimmer control board to look for the DMX input, you might be able to see what's wrong.

I do hope ETC has the good sense to socket that input chip, and to not use surface mount components in the section vulnerable to outside influences.

If you still have reason to suspect building wiring, disconnect the cabling and connect a short DMX cable directly to the dimmer rack, then test the consoles. That'll eliminate a lot of variables in one step.