broken dimmers


Well-Known Member
OK, my school has 3 ETC smartpack dimmers, 1.2 kw, 12 circuits each (so total 36). 3 of them are not working, one on each dimmer rack. on rack 1, dimmer 11 is full on. i plugged the 750 watt S4 PAR into it. I flipped the breaker for that dimmer and the light went on. I verified that the board wasn't sending a signal or that the dimmer was testing it. I turned the dimmer off and on again (it usually works with computers......) and that didn't change anything.

Rack 2, Dimmer 22. This is confusing me..... I pluged the light in. I ran a dimmer test on it, it worked fine. I tried to turn it on from the board and it wouldn't go on. the strange thing is that the dimmer told me that it was receiving the signal from the board, but the light won't turn on......

Rack 3, Dimmer 30somad, same thing as dimmer 11, full on.....

we got these dimmers new from ETC, so they should be on warrantee. We've got 4 shows coming up, but after that we might want to send them in.

tried yelling at them, and that didn't work either.... I'm thinking about sending them into ETC if I can't figure out whats wrong, but I if theres something clearly that i'm doing wrong, or that I haven't tried yet, please do enlighten me.... we're running single phase, if that helps....

Hmmm - can't say that I am familiar with these dimmers and given that they are under warranty and that you have shows coming up, you may well be better off giving the ETC service tech a call.

Three new dimmers all falling over at the same time would suggest that the problem may be related to something other than the dimmers BUT it wouldn't be the first time that 3 units have failed at the same time.

I am assuming that you have done the standard things like checking the termination of your DMX, the DMX leads, and the addressing of the dimmers. Swap leads between dimmers/desk, re-address etc and run them up individually to see it the problems persist.

With the dimmers that are staying on (in the absence of the test function), I would be leaning towards a dead optocoupler, for which you are going to have to get the unit serviced. If they are under warranty, then you are going to have to get an authorised ETC service centre to do the work or you will void that warrenty.

If it were me, I would be calling ETC and asking them their advice. For the time that you spend waiting for an solution your dimmers could be back up an running - especially if the only advice you get is mine (one would hope not). The last thing that you want is further problems occuring during your shows.

All the best!
Very true. I have 4 shows in the next 3 weeks though, so I need to wait untill after that to send them in/call them. I am just trying to make sure that it is not a problem on my end, and that the dimmers really are broken. I wouldn't be surprised if rack 1 was made incorrectly, as the front key pad was installed up-side-down and I already (or, rather, the lighting teacher who knows the dimmers better) opened them up and fixed one problem (a chip wasn't installed right, so a third of the dimmers wouldn't work).

about terminatng the dmx line, the dimmers should terminate the line by its self, and I shouldn't need to buy anything else to terminate the dmx line. the dmx line is only connected from the bored to rack 1, then daisy chained from rack 1 to rack 2 and from rack 2 to rack 3. I was under the impression that rack 3 should be terminating the dmx line by its self, and that I don't need any additional hardware to terminate the line.
I'd still give their service department or a local registered service depatment a call and seek their advice. If a problem exists with the dimmers, then you should be asking for replacement units whilst yours are being fixed

I was always taught to terminate the end of every DMX run and it is worth giving it a go (it cannot hurt). All you need is an XLR (3 or 5 pin depending on your dimmer) with a 120 ohm resistor soldered between pins 2 and 3.

Let me know how you get on
Haha, i find it ironic that this post got dredged up after all these years (posted first August 2004) today since I have another problem, unrelated, with the dimmers.

This problem, by the way, was that the dimmer packs cubes had failed full on. This was a known problem with the packs and a call to ETC got them to send replacement parts and directions with how to replace the cubes for free.

When in doubt with ETC equipment, call ETC Tech Support, as i have no doubt they can solve any problem you throw at them.

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