Leviton D4DMX dimmer nightmares

[JD]

I stumbled across this thread looking for technical documentation on one of these dimmers because I bought it used and like many other folks it had several shorted channels.

I happen to own some really old NSI equipment and it is sad to see how they have 'cheapened' their product offering over the years. I have never been a big fan of triacs for dimmers. I always preferred a dual-scr design. Sure a triac is nothing more than two SCR's packaged into one case but if you look at the thermal capacity of a dual-scr design vs a triac the dual-scr design always wins out even with the same current rating.

I have an NRD-8000 and an ND4600, both of them a virtually indestructible. Each individual SCR has a large heat sink per device, then you look at the D4DMX it has one single heat sink shared by 4 devices and then also relies on the heat to be distributed to the back mounting cover yet there is no heat sink grease to help conduct the heat to the rear panel.... very poor design indeed...

If there is only one good thing about the design it's that they still included chokes on each channel. I've seen really cheap Chinese crap with no filters at all or a single filter for all channels... those things put so much garbage on the line I've seen some of them actually generate enough noise to throw the gating/ramp signal into a tither within the dimmer pack itself.

Most modern commercial dimmers these days use SSRs (Solid State Relay) for the power end, as compared to discreet SCRs or Triacs. Basically, a monolithic device that contains the opto isolator, firing circuit, and thrysistor all in one part. At its heart, that thrysistor could be a triac or set of SCRs, but unless the part manufacturer tips his/her hat, we will never know
Back to the "shoebox" NSI, as long as you have 25 amp triacs in there, they hold up pretty good. Shame they come with 15's. Modern triacs and SCRs are better at handling some of the real high current spikes the the old beasts, but I must admit, it was pretty hard to take down some of those old back-to-back SCR dimmers.

 

[Floobydust]

Kinda late for me to chime in to the Original Poster, but I've had some shoebox or treepack dimmers that had a problem with the DMX signal timing and did erratic things like the D4DMX unit; changing the Break time to at least 200 micro seconds seemed to solve the problems.

Doug Fleenor Designs has a unit and so does DMXKing.com that will re-time the DMX signal.

My two cents worth.

 

[florentinian]

I'm new to theatrical lighting (after a career in software and software-controlled hardware. A small playhouse here has been having long-term grief with their lighting and I 'volunteered' to see if I could help (I was tired of paying to watch 'strobelight' theater). The gear is 6-7 years old-- a Leviton MC-7016 controller and three D4DMX dimmer packs (bought new). Stage lights apparently have always flickered sporadically, plus the dimmers run hot, though the lighting loads are modest and well below Leviton's per-channel and unit recommendations. Some of the flicker was caused by worn/dirty crossfader sliders in the MC-7016. Cleaning them helped a little, but we live on the Pacific coast (where we clean sand from our gutters instead of leaves and salt air corrodes everything). So I replaced the two sliders and that helped some more. The remaining flicker was analog-noise related and switching from Microplex to DMX digital protocol resolved that. The lighting is now flicker-free.

My questions relate to the dimmer packs. On opening the D4DMX's for inspection/cleaning, I was pretty surprised to find the output AC receptacles were connected to the PCB using only the spring-loaded push-in rear connectors on the receptacles -- in fact the receptacles don't even have screw-down connectors except for the ground wire (ironically, the receptacles aren't made by Leviton either). That led me to look for the UL seal, only to realize there isn't one. On the hottest-running dimmer pack, three of the push-in receptacle connectors would pinwheel freely and when I pulled the neutral output leads from their lugs on the PCB, the lugs themselves came off instead of the connector -- the damn wires had gotten hot enough to semi-unsolder the lugs from the PCB!

Needless to say, I'm not very impressed with these dimmer packs. They look like a fire waiting to happen, the triacs look like they were spec'ed for 220V operation and no one considered what that would mean in a 110V market like the US (where the current is doubled). I can replace the receptacles with commercial rear-screw units, resolder all the power lugs on the PCB, and upgrade the triacs with something beefier for probably less than $20 a unit (I work cheap). I'd prefer not to tell the theater owner he ought to deep-six these units. My question is: "What else does everybody know?", or, are there any other gotchas awaiting me with respect to these units. Any advice would be appreciated. I realize they're entry-level units and all, but damn, no UL certification? I didn't even think that was legal (or if legal, not very smart). My opinion of Leviton has dropped considerably.

Anyway, thanks in advance for any insights/warnings. I've already learned a lot from this forum, and want to thank its forum members for sharing their hard-gained knowledge.

 

[gafftaper]

Welcome to the Booth! I love the Oregon Coast. My family makes the Pilgrimage down from Seattle at least once a year.

Yeah unfortunately, you have low grade dimmers and you get what you pay for. If you want to buy dimmers with no UL rating, they are readily available. Will they continue to work for long? Probably not. What you describe is not at all surprising to me. It sounds like you have the skills and brains to do your own rewiring and upgrading work on the dimmer packs which is great. But it's not the kind of thing we recommend around here because it's too easy to start a fire with a little mistake, especially when you are working with such low quality equipment. What should you do? Throw them away and spend a couple grand on some decent dimmers. Is that likely to happen? Yeah, of course not. So you do what you have to do to keep them going.

The best advice I have is make sure a qualified electrician inspects anything you choose to do before you plug it in during show conditions... and start saving your money for a decent dimmer pack.

(Moving this thread to the Lighting forum. The new member forum is really just for saying hello. You'll get more information in the lighting forum.)

 

[len]

I have a bunch of these and I have never experienced the heat issue. I will say that I only put 2 x 575 HPL loads on them at a time (at most). Part of your issue may be environmental, and nothing anyone can do about that. If they're that old, I'd say it's time to move on regardless of how good your experience with them has been. I've also used these a lot and they're pretty solid. http://www.leprecon.com/support/product/33

What about using a permanently installed dimmer rack? Considerably more expensive, but considerably more durable.

 

[gafftaper]

Leprecon is definitely a good moderately priced decent quality solution to consider if you are going to replace them. ETC and Strand make the best dimmers, but you pay a lot for that reliability and they too will struggle with that salt air. Or you can go with the cheap ones from Chauvet/Elation. They will be fine for a while and when they go out because of the salt water in the air, they are cheap enough to consider them disposable and buy new ones. I think I like that solution if you are thinking about replacement.

 

[BobHealey]

The Lepreon units are also sealed units, using the chassis as a heat sink instead of relying on air flow through. That might help keep the salt air away from the electronics inside.

 

[gafftaper]

Now the really important question. I haven't been down as far south as Florence in a few years. Has the Fred Meyer been swallowed by the Sand Dunes yet?

 

[JD]

Check around the forum a bit, thee are a couple of good threads covering the servicing of this and it's competitors from Elation and Chauvet. There is a 25 amp triac that subs just fine. Consider the packs to be 600 watts per channel with an 1800 watt pack limit and they should serve you well. They are low end dimmers and I have been down the road of changing out the connectors as well as eliminating the spade lugs as these are weak points.

The Warning: The usual "Only by a qualified servicer" applies as I would not want anybody to be working on something that could cause a fire or death. If the packs are new, remember that working on them voids the warranty. If they have UL certification, modifying them causes them to no longer be certified.

 

[florentinian]

Now the really important question. I haven't been down as far south as Florence in a few years. Has the Fred Meyer been swallowed by the Sand Dunes yet?

They have a "win-win" arrangement with a landscaping materials contractor next door. He regularly drives a front-end loader and dump truck across the street and into the back of the F/M lot to replenish his "sand" bin.

 

[florentinian]

Check around the forum a bit, thee are a couple of good threads covering the servicing of this and it's competitors from Elation and Chauvet. There is a 25 amp triac that subs just fine. Consider the packs to be 600 watts per channel with an 1800 watt pack limit and they should serve you well. They are low end dimmers and I have been down the road of changing out the connectors as well as eliminating the spade lugs as these are weak points.

The Warning: The usual "Only by a qualified servicer" applies as I would not want anybody to be working on something that could cause a fire or death. If the packs are new, remember that working on them voids the warranty. If they have UL certification, modifying them causes them to no longer be certified.

I've upgraded two of the three units to BTA24's from the original BTA16's and I'll do the third one shortly. Fried triacs on one pack was what got me involved in the first place; a 16A triac to chop up a 10A load at 110V is pretty optimistic, but about right if you're running a 5A load at 220V. I'm just about certain the heat is related to the crappy spring-tension connectors on the load receptacles. The packs are way out of warranty, they have no UL/CSA certification (if they did, I doubt I'd be having to work on any of this). As to "qualified servicer", well, I agree in theory. But who's qualified? Leviton seems to have gone down the same path as General Motors with their ignition keys. I do take your admonition very seriously though -- I only wish Leviton did. Frankly the D4DMX units look like their last design cycle was done by an MBA instead of an engineer.

 

[florentinian]

They have a "win-win" arrangement with a landscaping materials contractor next door. He regularly drives a front-end loader and dump truck across the street and into the back of the F/M lot to replenish his "sand" bin.

A trivial pursuit question: Did you know Frank Herbert got the inspiration for his Dune saga from the sands dunes here in Florence? There's a large collection of his research material on permanent display in our public library (The Frank Herbert Room).

 

[gafftaper]

They have a "win-win" arrangement with a landscaping materials contractor next door. He regularly drives a front-end loader and dump truck across the street and into the back of the F/M lot to replenish his "sand" bin.

Ha! That's awesome! Although it strikes me as odd that anyone in Florence would need to buy sand.

A trivial pursuit question: Did you know Frank Herbert got the inspiration for his Dune saga from the sands dunes here in Florence? There's a large collection of his research material on permanent display in our public library (The Frank Herbert Room).

That's crazy! That I did not know.

 

[techieman33]

Frankly the D4DMX units look like their last design cycle was done by an MBA instead of an engineer.

Pretty much. Dimmers like these were designed for the low end DJ market. Now churches and theaters are using them and asking more from them then they were really meant to ever do.

 

[Terry Simpson]

Similar sort of issues. 5 years ago, I bought 4 of these leviton d4dmx-md3 For a Fitness Center project. We have 36 LEDs, but I use these as DMX-Relay switches for Blacklight (4' UV floros), and they have worked fine, with very little use (maybe 50 hours in 5 years). (I also recently bought 14 of the 5-wire DMX version for our Film School studio, where they will be used mostly on Tungsten fixtures). Anyway, we were having (suddenly) a bunch of issues with whole DMX runs crapping out (until you broke the daisy chain, when the light you were working on popped on), Anyway, in trouble shooting the whole system (I think a bad cable or 2, some Addresses had gotten changed by the cleaners dusting, and the panel Terminator had gotten pushed, and was double-terminating), AND I found out that the CHannel control on this one unit could NOT be changed, it only reads "CH00" (instead of CH01, CH02, or CH04, like the others show). It is not LOCKED. No combination of button pushing makes it change. The Program (P01) mode does not cycle through channels. Any ideas? Is it just fried? Anyone seen this before? Any help appreciated.

 

[florentinian]

My thoughts: (1) Disconnect all data cabling before trying to diagnose D4DMX configuration issues. (2) Make sure the "cleaners" didn't randomly reconfigure the unit to Microplex protocol. (3) Add dimmer packs one-at-a-time and verify correct operation before adding the next cable and dimmer pack. (4) Make sure you haven't inadvertently plugged a DMX cable into a Microplex port (not likely on at the 5-wire versions). I've done all of these dumb things myself, so please don't take offense at my suggestions.

The issues with the Up/Down push buttons not operating could indicate a failure on the control side of the printed circuit board, or it could simply be a mechanical issue (e.g., a corn-chip fragment has gotten under the case cover and is interfering with button operation). As a simple test of the latter, disconnect power and data, take the back off the case (9 screws), then loosen (but don't remove) the five screws that mount the PCB to the case. Wiggle the board a bit and use a can of compressed air to blow under the board (particularly around the buttons). Press all the buttons and verify they all "feel" the same. Then tighten everything up and replace the cover. That may do it. If not, unless you know a PCB repair technician, you've got a dead dimmer.

Also, while the case is open, examine the condition of the wires going to the outlet receptacles (especially the neutral/white wires). If they show any sign of scorching/heat damage, I strongly suggest you consider replacing the cheesy spring-contact receptacles provided by Leviton with screw-down, back-wired receptacles from your local hardware store -- your fire insurance carrier will thank you.

 

[Terry Simpson]

1) Done, 2) DMX, and 3) benchtesting it. No diff.
The insides looked very good, hardly even any dust after 5 years. Buttons were not the problem because they work perfectly for all other menues. Another clue: putting it into P01 (simple chase thru all channels) did NOT light any LED's or lights connected.

FYI, my next step was to call NSI at 800-824-3005, work through the menuses to talk to Tech Support, the receptionist took some info, and said a Tech would call back within 24 hours. Got a call from Bill the next morning. He was great! Very friendly (said he was pleased to hear that these were even working after 5 years), after taking me thru menues and establishing that I was describing things correctly, he tried one reset: turn off, hold all 4 buttons while powering up (factory reset?). Anyway, it should have reset everything, including A001-instead it still showed A262. His diagnosis: hardware problem, needs fixing. $97 flatrate, plus ~$20-30 shipping to him (they pay for return and give 90-day guarantee), all standard--meaning 4-5 weeks turnaround. Expedited gets it fixed in a week for $30 more. My decision: Full Compass sells these for $145 now, with a 2-year guarantee. No Contest. We are truly in a throwaway society. Thank you all. Hope that helps others.

 

[JD]

Put it in your "turkey carcass" pile. Sooner or later you'll need to pick some parts off it.