Dimmer Box catching on fire

[joshthesoundguy]

ok so i am having a problem with one of our dimmer packs for pars. it is a NSI N600P-D2K 4 Channel Dimmer Pack. we had some lights out on our youth stage in the gym and i went up to replace the bulbs because some of them were burned out. i replaced the bulbs and tried turning them on but they still did not turn on. i grabbed an extension cord and plugged the lights straight into the wall and they all turned on. so after i traced all the power lines back to the dimmer box and made sure they were plugged in correctly i tried again and they still did nothing. i then tried looking at the fuses in the dimmer pack, they all seemed fine so i just re-seated them and then tried to turn it on one final time. this time the box started sparking like crazy and we turned it off immediately. does anyone have any idea what might of happened and how to fix it?

[daver2]

First of all - welcome to CMN Josh the sound guy.

There are many causes of sparks leaping out of equipment. The one that springs to mind first is a disconnected mains live cable inside. This would account for the initial lack of operation and no sparks if the live had been disconnected from the dimmer internally but was not shorting out to (say) neutral or earth. Possibly reseating the fuses has dislodged the live wire and it is now making contact with a neutral or earth wire - or some other internal part of the electronics.

The thing that concerns me is that the mains fuse did not appear to blow when the fault occurred.

Since you mention youth in your post - I would strongly suggest that this piece of equipment is either repaired professionally or is scrapped altogether otherwise someone may get killed or injured.

Dave

[petereit]

Yep, I say you punctured the "sparks" container inside the dimmer. Since it's impossible to get sparks back in once they've escaped, the whole fixture is now Evil and needs to be permanently excorcised.

[Gracetech]

If you are getting sparking from a dimmer then someone probably put in fuses that are higher rated than they should be and have burnt up the SCR's. Your SCR are what are giving out and sparking otherwise you would have had blown fuses.

crt

[Steve Vanciel]

Originally Posted by daver2

a disconnected mains live cable inside.

I second this motion. Could be due to a loose connection that eventually heated up enough to burn through the wire and leave it free to bounce around until it made contact with something and then sparks fly. Have seen this happen on various types of gear.

Also, double check your lamp wattages. The maximum for each of the four channels is 1200W. Easy to exceed if you're not careful.

SteveV

[D.R.HADDOCK]

There are many possibilities for sparking,
Faulty mains connections, faulty fuse holders, faulty triacs.
You really need to open it up, and look first for the obvious things,
What loading do you have on the dimmers ?