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[Thomas Berry]

I do sound at a local music venue, and by default handle the house lights.  The lights are 16 Source four juniors with 575 watt lamps plugged into 4 optima dimmers (1 fixture per channel), controlled by a chauvet Stage Designer 50.  I think we need more robust dimmers, but the immediate problem is that two of the dimmers have one channel that does not respond to commands.  If the fixture is plugged in, it is on full.  When I checked manual dimming and on/off at the dimmer, each is set to manual dimming at 000 and manual on/off at on.  The other channels have the same settings, and respond normally to commands from the controller.  Interestingly, it is channel 3 in each dimmer.  There are two more four channel dimmers in the system controlling four 300 watt oar cans each (1 per channel).  have done a few searches (here and google) and haven't come up with anything.  Is there a hard reset for these units?  For now am leaving this two fixtures unplugged (have to climb a 14 foot extension ladder to access them).  Thanks in advance.  If I have left out essential info, sorry.  I'm not a lighting guy, just the only guy there.

[Don T. Williams]

There is not a reset.  Those dimmer channels have failed.  Most modern dimmers use dual scr's or triacs (which are back to back scr's in a package) in the dimming circuit.  When these fail they fail "full on".  From your symptoms, there is a 99% probability that the triacs are bad.

On some of the "4 Pack" dimmers these are very easy to replace, quiet inexpensive, but it usually requires unsoldering and soldering.

For a good tech, its an easy fix.

[Thomas Berry]

Thanks.  I don't know much about lights, so all help is appreciated.

[Thomas Berry]

Followup question - as these dimmers are rated at 15 amps total, should we upgrade to dimmers with a higher overall rating? Say 20 amps?  I've been doing some research on this and such dimmers exist.  Any recommendations? Or, perhaps more importantly, brands to avoid?  Thanks again.

[TJ (Tom) Cornish]

Followup question - as these dimmers are rated at 15 amps total, should we upgrade to dimmers with a higher overall rating? Say 20 amps?  I've been doing some research on this and such dimmers exist.  Any recommendations? Or, perhaps more importantly, brands to avoid?  Thanks again.

4 575w fixtures on a 15A pack is too much, but that should have blown the pack breaker, not the SCR module.

If your circuit is stiff enough you may be able to run 4 575w fixtures on a 20A pack, but to be safe, it's better to get something that does 3 fixtures per circuit - either artificially by not using the fourth dimmer, or by getting a high power style pack like the Leprecon ULD HP series, or the cheaper and lower quality Elation. These have 2 input cords and 6 dimmers per box.

[Jeff Lelko]

I have mixed experiences with Optima dimmers.  The 'old' Matrix dimmers (dark blue in color) have worked very well for me while the 'new' Matrix Pro dimmers are terrible.  The reason I bring this up is that after having issues with the new model and contacting Optima directly about it, the problem was actually due to a firmware bug.  Some units were affected and some weren't.  I agree with Don in that most likely the channel is shot, but there have been known firmware issues with these packs as well.  Do you know exactly which model you're working with?   

The 20A per pack rating is another interesting point that you bring up.  My old Optima dimmers claim a 20A rating and my very similar Elation dimmers claim the same, however since both have the molded 5-15 plug on them wouldn't that still mean you're in a grey area if you load them up beyond 15A (assuming you don't chop the plug off and wire your own)?

[TJ (Tom) Cornish]

I have mixed experiences with Optima dimmers.  The 'old' Matrix dimmers (dark blue in color) have worked very well for me while the 'new' Matrix Pro dimmers are terrible.  The reason I bring this up is that after having issues with the new model and contacting Optima directly about it, the problem was actually due to a firmware bug.  Some units were affected and some weren't.  I agree with Don in that most likely the channel is shot, but there have been known firmware issues with these packs as well.  Do you know exactly which model you're working with?   

The 20A per pack rating is another interesting point that you bring up.  My old Optima dimmers claim a 20A rating and my very similar Elation dimmers claim the same, however since both have the molded 5-15 plug on them wouldn't that still mean you're in a grey area if you load them up beyond 15A (assuming you don't chop the plug off and wire your own)?

Jeff, it's probably a UL issue.  I own the both the 6-channel Elation dimmers with 2 input cords and the Leprecon ULD series.  Both are technically rated at 15A per input cord (even though they have 5-20P plugs on them), but the SCRs are rated at 20A/channel (actually the Leprecon ones are 25A per channel for some headroom).  Leprecon goes so far as to sell two models - the UL-listed version rated at 15A per cord, and a non-listed version rated at 20A per cord, the only difference being the rating of the pack's circuit breaker.

IMO the 575w bulb standard is awkward.  It was designed that way as part of ETC's larger universe of products, especially the Sensor dimmer racks which are rated for 20A/channel continuous.  If you use 575w fixtures with an ETC system, 4 fixtures per dimmer channel is no problem.  If you use them with anything else, either you are pushing your luck with 4 fixtures at 2300w of load on a 20A circuit (which can quickly rise significantly higher than that if your venue voltage runs a little high), or you run 3 fixtures totaling 1725w which leaves quite a bit of headroom on a 20A circuit, but is pretty tight on a 15A circuit.

This issue is partially addressed this by the availability both 115V and 120V versions of the bulbs, so if you buy the 120V version you will have a little more headroom and/or tolerance to high supply voltage at the cost of slightly less output.

For my purposes, 575w is often more power than I need. Next time I do a bulb order I'm going to test out some of the 375w bulbs.

[Terry Martin]

I've had to replace a triac or two on those packs before.  Relatively simple. 


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[Jeff Lelko]

Jeff, it's probably a UL issue.  I own the both the 6-channel Elation dimmers with 2 input cords and the Leprecon ULD series.  Both are technically rated at 15A per input cord (even though they have 5-20P plugs on them), but the SCRs are rated at 20A/channel (actually the Leprecon ones are 25A per channel for some headroom).  Leprecon goes so far as to sell two models - the UL-listed version rated at 15A per cord, and a non-listed version rated at 20A per cord, the only difference being the rating of the pack's circuit breaker.

Very interesting.  Thanks for the explanation!

[Thomas Berry]

Thanks so much for the info.  I am thinking we probably need to upgrade the dimmers, as this seems the logical solution.  We like the source fours in terms of lighting, so probably will go with the higher rated dimmers.  I'm thinking the elations as we probably cannot afford the leprecons.  I am learning.  I will probably fix the two bad channels, if for no other reason so we can sell the dimmer packs.  Thanks again.

[ProSoundWeb Community]