Control/Dimming Repairing Chauvet DMX-4 dimmers.

gafftapegreenia

gafftapegreenia

CBMod
CB Mods
Hey CB.

So we have three Chauvet DMX-4 dimmers. The older silver ones before they changed the color to black. Certainly not a fancy or expensive dimmer, but useful for Christmas lights and other small wattage loads. They have been handy distributed dimming supplements to our main system. Anyway, at least half the channels have stopped working, they are either stuck at 0 intensity or stuck at full. I was wondering how hard it is to replace the triac in these units, as I'm sure someone on here has done it before. If not, I know they are cheap dimmer packs, and it won't break us to buy new packs. I'm just investigating my options at this point and thought I would see if anyone on CB has had experience repairing these or similar quality DJ style packs.

Of course, I have started to dive into past CB threads on this topic, but I'm really looking for tips on doing the actual repair itselfs and which triacs to use.

Unfortunately our packs are in use for a show right now, but I can open one up on Monday to get a look at the triacs.
 
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Are you sure they didn't get changed to "relay?" If they're similar to Leviton and Elation dimmers, it's easy to do that.
 
I work for a church that has a few of these with bad channels as you have described, interested in hearing about the repair!
 
Depending on your level of soldering skills, there are several approaches to try. Mnay of these "shoebox dimmers", have the triacs mounted to a heatsink that is set off and to the edge of the circuit board. With these, you can cut the leads of the triac as close to the triac as possible. Now if you have a solder sucking iron, you can heat and remove the lead by sucking the solder from the front of the circuit board while extracting the lead from the back of the board with small longnose pliers or a hemostat.
Once the lead is removed, make sure that the hole is clear of solder enough to insert a new lead. This can be done with a solder sucking iron, solder sucker and regular soldering iron or solder wick. all of these are available at Radio Shack or mpja.com. Remove the old triac from the heat sink, (usually held with one screw), carefully bend the leads of the new triac in such a way that it can have the leads inserted from the back of the board. Then bend the triac down to where it fits on the heatsink and secure with the screw removed before. Before securing put some heatsink compound between the triac and the heatsink. If there is none available, and you are in a hurry, try and use the new triac back surface as a scraper to scrape the compound from the old triac. Once the triac is secure, solder the connections at the board.
One option to try if you are not proficient in soldering, and afraid of putting too much heat on the board when soldering, would be to leave the leads that were cut from the old triac still in the circuit board. Mount the new triac, and trim the leads so that they can lay right on top of the old ones, and solder the two leads together. This method while not the best, is better than burning the circuit board or heating too much and delaminating the circuit traces.
Some of these type dimmers, have the triac under the circuit board and completely not visible. (Lightronics comes to mind). With these, it become necessary to remove the circuit board and the screws that heatsink the triacs. Before doing, make drawings of wiring colors and connections, and size of screw and from where it was removed. Cell phone pix are pretty good for this task. When you put the new triac in place, do not solder it to the board. Just leave the leads sticking through the board. Now mount the board and triac, insuring that the leads remainin in the holes as all of the components are remounted. Once everything is secure, solder the leads.
Most of the dimmer packs come with triacs that are rated slightly above the suggested load. Usually 10 to 16 amps. Replace with 20 or 24 amp triacs. Also when purchasing new triacs, make sure that they are the type that the heatsink tab is isolated from the leads.
Just as an example of a reason for upgrading the amperage capability of the triac is such: The larger and more expensive dimmer racks use SCRs or Solid state relays that are rated at 40 amps for 20 amp circuits. This doublilng of capacity allows for in rush current, and means that there is less chance for damage. In the less expensive packs, they advertise 6 amp and 10 amp limits per channel, but use 10 amp and 16 amp triacs. By replacing with a 20 or 24 amp triac, you are improving the chances of less failures, more like the larger dimmer systems. Also many of the Chinese manufactured dimmer packs use a triac that is so cheap that they don't even put a manufacture name or model on it. When purchasing Triacs from Mouser, Digikey or future electronics, you are getting a top brand triac.
I hope this has been useful, I usually keep 20 or so brand name 24 amp triacs on hand, and fix the packs for about 6 theatres in the area.
 
I replaced all four in mine after someone (who won't be named) tried to run four, 1000w PAR's on it. :confused: Bought them from Mouser for about $6 including shipping. It wasn't a simple solder job, but with a bit of patience and care, it can be done by someone with moderately decent soldering skills (me).
 
It's dead simple really. The insides:
Chauvet_DMX4_inside.jpg
Heed the advice of JD or dramatech: Use larger (capacity) than stock when you replace them. One or both have posted the part#, probably in one of the above-cited threads.
 
The link I posted was from 2008. At that time, I changed out all of the triacs on all of the shoebox dimmers I had. It has now been 5 years, and I haven't lost a channel, so the 25 amp triacs are a real improvement. By the time I got to the 4th pack, it was taking about 20 minutes per pack at a cost of about $8 for all 4.

As mentioned by dramatech, you must use the insulated tab triacs or things will go BANG when you plug the pack in.
 
Thanks for all the advice everyone, exactly what I needed to know. :)
 
So Mouser has a couple different Triacs in the 600 volt 25 amp range. Which is the part # I want?
 
Ok, need to pick the collective mind of CB again.

One of my Chauvet packs is missing the screw in part of the fuse holder? I doubt that this holder is Chauvet specific. Anyone know where to easily obtain this piece before I slog through Mouser/Digikey?
 
The fuse holders say MF527 on them. Sure enough, plenty of them on eBay!

As an aside, why are we still using cartridge fuses? Especially the bayonet style holders that break if you look at them the wrong way. Why not auto style fuses?
 
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Since this thread has skewed a bit I'll ask this here.......I have an Elation DP-415 that shows OK on the control side and power side but no output is happening. Anyone know where if A) this is worth having serviced and B) where would I obtain such service? I have been round and round the 'net to no avail.....
 
danhr said:
Since this thread has skewed a bit I'll ask this here.......I have an Elation DP-415 that shows OK on the control side and power side but no output is happening. Anyone know where if A) this is worth having serviced and B) where would I obtain such service? I have been round and round the 'net to no avail.....
Click to expand...

OK, let's narrow this down a bit. The "power" LED is on, and when you connect the board, the DMX LED is on. Is this what you are seeing?

If so, the next thing to look at is; Do the channel indicator LEDs light up when you bring the channels up?

If not, you probably have an addressing or communication issue as compared to a pack failure.

If they do, and you have no AC output on the receptacles, and you have checked the fuses, then you may have a failed pack. Generally, when they do fail, they stick on at 100% so it is a little unusual to see one fail where there is simply no output. Still, it does happen.

Lets us know what you find out, and hopefully we will be able to direct you to somewhere local for service.
 
Data is OK- power, DMX alive, and channel lights normal. 120v present up to input of all 4 triacs, zero output from all.
 
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