NSI ND4600

[The Dude]

Howdy Folks,

I'm looking for a schematic for an NSI ND4600 dimmer pack. Searched here, searched Google, other usual suspects, and can't find one anywere. Any tips/help will be appreciated.

Thanks in advance!

[Enzo]

Did you contact NSI directly and ask for it?

I have it here somewhere, and if I can find it, I'll try to scan it in for you, but they would be probably faster. I used to fix a lot of those.

[The Dude]

I did contact NSI and they were supposed to email it to me. I can certainly contact them again, but thought I'd try here for a quicker response. They are either very slow, or there was a problem.

I've fixed a lot of these myself, but it's not the usual problems (transformer, SCR, logic chips). This one got wet, and I believe it's likely a trace or feedthrough that got "eaten up". It would be easier to track down with a "map". I've already swapped out all the chips. They're in sockets and I keep subs just for these units. At the price of the chips, it's often easier to just sub out chips 'till they work. Not the case here.

Anyway, thanks for your reply, and if you do come up with the scan, I'll take it. In the mean time, I'll hit up NSI again.

[Enzo]

Well I hate to bug them, hard to say how far under-manned they might be. Always use terms like "my customer" and "my customer's unit."



I'll see if I can dig it out, I haven;t done much lighting the last several years, so my manuals are not nearby for lighting stuff, and I didn;t scan things in back then.


4600, is that the fairly simple one - four in a row on the board? Or is that the one with basically a pair of two channel dimmers, one on each side with aluminum heatsinks. Or am I thinking of the 4900? Or the one with two power cords? Or some of those descriptions might be the same model.

I seem to recal a bunch of diodes, and the multiplexed control signal was split into the dimmer level stairsteps, and a sort of sync pulse on the negative side. If that description makesd any sense.

My shop used to share a building with a sound production company/retailer AND a lighting company, and I fixed stuff for those companies as well aqs my own customers. The lighting guys rented out basic NSI systems, with that basic floor pedal with the slope front and sliders. Just about every time they rented it out, it came back with half the sliders busted off. Those poor circuit boards shed their copper traces after so many replacement silders.

[Mark Black]

The ND4600 (600W/Chan) and ND5000 (1200W/Chan) are basically the same, with larger SCR heatsinks as well as larger ampacity inductors and channel fuses on the ND5000. And then there is the NRD8000 rack-mount dimmer which contains two ND5000 circuit boards. There are at least a couple different versions of each with the most easily recognizable difference being the channel fuse layout (later = 1-4 pretty much inline with the respective channels or earlier = all channel fuses grouped to one side). There are also other circuit differences between versions which allow the later dimmers to recognize and deal with more than 32 channels of info.

Here are a couple versions (by way of the NRD8000 route):

[Enzo]

Cool. I found my 4600 drawing, and yours is nicer.

[The Dude]

Sorry for the late reply, but I was out of town and just got back into the shop. Anyway,...thanks much Mark (you too, Enzo)! I'll update when I get this thing figured out.

[The Dude]

This is not a "normal" failure and therefore likely useless information, but posting anyway in case anyone's curious.

1) Found good clock out of U1 pin 1, but not on the other side of D13. It was there, but barely visible on the scope. Probably less than .05V peak to peak.
2) Pulled U3 and U2 out of sockets and clock still low. Also checked D13 and D14. Both were good.
3) Measured from D13 cathode to ground (basically accross R22) and measured about 3k instead of the expected 4.7k.
4) Removed chip socket for U3 and found residue underneath socket from apparent spill/leak into dimmer.
5) Cleaned off residue on PCB and chip socket and reinstalled socket.
6) Re-measured accross R22 and got the expected 4.7k.
7) Reinstalled board, hooked up all connections and tested......ALL GOOD!

Thanks much for your help! This would have been difficult if not impossible to chase down without a proper schematic.

[Enzo]

That is a good story, because the same thing happens all the time in most any kind of gear. One thing I preach in training is that not all problems are due to bad parts.

[sounddoctorin]

for some reason that's coming up blank for me. I wonder if it expired or something. Was just going to work on one of these and it'd be swell

[sounddoctorin]

ps it's got a pdf in the name but says it's loading a gif? But it's just black

[Enzo]

We had a server crash a few years ago that blanked most of our stored files.

The attachment may or may not work. However NSI is a division of Leviton, and you might get the file from them directly.