Control/Dimming NSI DDS 5560 Shoebox Dimmer

[Lotos]

Alright, quick question for any of you out there that own these, or have come across them in the past...

I'm sitting here at my bench today, taking a break from TP-22 replacements, to stop and look at our Shoebox Dimmers... We use several to suppliment our existing 1.2k & 2.4k racks, as they're handy to just toss on the back of a set piece, and run practicals with...

I have three of these older NSI DDS 5600 units (now we buy Leviton D4DMX, but I digress)... Each and every one of them has a dead channel that I'm reparing...

Channel 1, on each of them, had at some point over it's lifetime blown a fuse... And that fuse had magically welded itself into the fuse holder... Three packs, three blown fuses, three stuck to the point the glass shatters upon attempted removal. (These are Surface Mount PCB 6.3x32mm Fuse Holders with 6A 250v FB Fuses)

Now I'm capable of desoldering these from the PCB, and replacing them, which is exactly what I'm doing... I'm just wondering if this is an issue with this particular model? Or a pure fluke...

I should note, these are different ages, different suppliers, same model, same issue....

Weird

 

[jonliles]

I've seen it on the NSI 4600 (MUX) Shoebox dimmers as well. I wonder if the PCB is the same design? Also, over time the power cable would oxidize so much that soooner or later the light loads would cause the connector to catastrophically failed. I made the theatre toss those - I got tired of repairing them.

 

[JD]

Not common but does happen. The glass fuses often have solder near the ends which may seep out and cause the fuse to solder to the fuse holder. Has more to do with the brand of fuse then anything else. When replacing, look for fuses that have clean ends without any trace of flux near where the metal meets the glass. More likely to happen on a brand new, shiny fuse holder too. I have even seen some cheap fuses that have solder on the end cap. Avoid those like the plague.