ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: NSI DDS 9800 dimmer problem  (Read 2146 times)

Alan Hamilton

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 341
NSI DDS 9800 dimmer problem
« on: September 01, 2005, 12:47:57 am »

I was asked to check out an issue with a rack of NSI DDS 9800 rackmount dimmers.

There are two problems and 1 I probably have a handle on but not the other. Pack #1 has 3 channels that are 'full on' regardless of input control or test button position. The amber light flashes on these channels IIRC. Disconnecting microplex IN and OUT on that pack made no difference. Does that seem unusual to lose 3 channels on one pack in an installed system in only about 3 years time? ...or are there some issues with the DDS 9800 packs?

The more perplexing issue seems to be dimmer #2. They tell me that some of the lights on that pack will begin pulsing at times regardless of controller settings (channels down, blackout, etc). Unfortunately, in my time there I didn't see the lights themselves pulse but I did notice the green LED indicator lights on some channels of that pack begin dimly pulsing after I was there a while. I disconnected the controller and this had no effect. I believe the unit might start this and the intensity slowly build until the lights noticably pulse. What would cause this?

No, it's not the chase on the brd running Wink

-AlanH



Logged
When I think of a witty saying I will put it here. Please note that my sig space is for rent Smile
http://www.HamiltonSystems.us

Ron Hebbard

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 287
Re: NSI DDS 9800 dimmer problem
« Reply #1 on: September 01, 2005, 01:17:53 am »

Hi Alan;

I'm no expert on NSI in general, or those dimmers in particular, but here are my thoughts.

Your three dimmers that are full on.
For these I'd strongly suspect the triacs, or back to back SCRs, are shorted.
This is often caused by folks plugging in a fixture, or extension cable, with a dead short.
They try it in one dimmer, it doesn't work, so they try it in the next dimmer.
The smarter users quit after blowing up two consecutive dimmers but some will blindly try three.

As to your second problem.
You mentioned disconnecting the board.
Did you also try disconnecting the control cable at the input to the dimmers along with any cable that may be looping on to other dimmers?  You mentioned trying this with the first pack but did you try it with pack two?
If the control protocol was DMX, I'd be enquiring about end of the line termination.  I've no real knowledge of Microplex so I don't know if it also requires termination.

Them's my thoughts.

Toodleoo!
Ron Hebbard
Logged

Alan Hamilton

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 341
Re: NSI DDS 9800 dimmer problem
« Reply #2 on: September 01, 2005, 02:18:13 am »

Ron Hebbard wrote on Thu, 01 September 2005 06:17



Your three dimmers that are full on.
For these I'd strongly suspect the triacs, or back to back SCRs, are shorted.
This is often caused by folks plugging in a fixture, or extension cable, with a dead short.
They try it in one dimmer, it doesn't work, so they try it in the next dimmer.
The smarter users quit after blowing up two consecutive dimmers but some will blindly try three.


That was my thought as well (as to the problem) but I doubt they were plugging any lights in/out since the packs are located away from the stage and the lights are far overhead. But you never know what idea someone may have and the extremes they will go to implement it! Wink


Quote:


As to your second problem.
You mentioned disconnecting the board.
Did you also try disconnecting the control cable at the input to the dimmers along with any cable that may be looping on to other dimmers?  You mentioned trying this with the first pack but did you try it with pack two?


As I was typing the original post it struck me that I don't think I did that with pack #2. I had been focused on pack #1 while also waiting to see the 'pulse' from the fixtures as described and time was short when I moved onto pack #2. It figures I'd skip an obvious step... But in my defense I was chasing down some other things as well.

Quote:


If the control protocol was DMX, I'd be enquiring about end of the line termination.  I've no real knowledge of Microplex so I don't know if it also requires termination.


To my knowledge Microplex doesn't require a termination.

Quote:


Them's my thoughts.

Toodleoo!
Ron Hebbard


Thanks!
-AlanH
Logged
When I think of a witty saying I will put it here. Please note that my sig space is for rent Smile
http://www.HamiltonSystems.us
Pages: [1]   Go Up
 

Page created in 0.112 seconds with 20 queries.