Help with NSI DDS8600

DanD

Member
I am so glad to have found this forum and I am looking forward to gaining much needed help/advise with my wife’s drama, choir, and band programs. She has a new job at a rural school here in Colorado, which has a nice stage with an incandescent lighting system. It has three NSI DDS8600 dimmers that are not working quite right. From what I have read on this forum, I believe they may need professional service beyond my electronics knowledge.

One issue I cannot resolve has to do with the temp sensor. It is a steady red LED. The documentation says:

TEMP (Red) - Steady indicates the dimmer is too hot and is preparing to shut down. Flashing indicates the dimmer has reduced levels or is shutting down in order to lower internal operating temperatures. (See FAN OPERATION and OVER TEMPERATURE.)

So, I have tried the following:

To adjust the temperature sensing of the DDS 88/9800( 86/9600 ) dimmers please see below;

IMPORTANT: BE SURE DIMMER PACK AT ROOM TEMPERATURE!!

1. Activate the calibration mode by holding down focus test switchs 4 and 8 ( 3 and 6 ) together for about 6 seconds. You will notice the fan runs at high speed , the line indicator LEDs begin to flash and the temp LED is on. NOTE: If the temp led is off no calibration is required.

2. Press focus test switch 2 ( 1 ) if calibration is low or focus test switch 3 ( 2 ) if high. You will notice the temp load indicator LED should go off indicating proper calibration.

3. Press focus test switch 4 and 8 ( 3 and 6 ) together to exit the temperature calibration mode.

There is still a constant red light. The fan stays on at a very low speed. No line indicators LEDs flash.

What does #2 above mean in reference to calibration being low or high?

Just one more thing for now: I found a guide on this forum that shows how to do a hard reset. What should this actually result in?

Thank you for any help.
 
When the unit is first turned on, the fan is supposed to run at full speed for 2 seconds as a self test. Does it do that? If not, that would point to a dying fan. Some fans have an RPM sensor, so it might sense a problem during startup and turn on the warning light. Fans are a very common electronic equipment failure because the bearings get contaminated with dirt and the lubrication turns to sludge with time. Fortunately, fan replacement is usually as easy matter.
 
Except in Yamaha StagePAS 400 where a $6 fan is buried 4 layers deep in sandwiched cat boards, and a hidden screw which has eluded me for a year holds that darn layer on. If anyone has the svc manual which Yamaha refuses to share, I'd be delighted. Ok, that was off track. But I started down the garden path of 'I have replaced zillions of fans, this should be easy ...' only to be humbled.
 
I am so glad to have found this forum and I am looking forward to gaining much needed help/advise with my wife’s drama, choir, and band programs. She has a new job at a rural school here in Colorado, which has a nice stage with an incandescent lighting system. It has three NSI DDS8600 dimmers that are not working quite right. From what I have read on this forum, I believe they may need professional service beyond my electronics knowledge.

One issue I cannot resolve has to do with the temp sensor. It is a steady red LED. The documentation says:

TEMP (Red) - Steady indicates the dimmer is too hot and is preparing to shut down. Flashing indicates the dimmer has reduced levels or is shutting down in order to lower internal operating temperatures. (See FAN OPERATION and OVER TEMPERATURE.)

So, I have tried the following:

To adjust the temperature sensing of the DDS 88/9800( 86/9600 ) dimmers please see below;

IMPORTANT: BE SURE DIMMER PACK AT ROOM TEMPERATURE!!

1. Activate the calibration mode by holding down focus test switchs 4 and 8 ( 3 and 6 ) together for about 6 seconds. You will notice the fan runs at high speed , the line indicator LEDs begin to flash and the temp LED is on. NOTE: If the temp led is off no calibration is required.

2. Press focus test switch 2 ( 1 ) if calibration is low or focus test switch 3 ( 2 ) if high. You will notice the temp load indicator LED should go off indicating proper calibration.

3. Press focus test switch 4 and 8 ( 3 and 6 ) together to exit the temperature calibration mode.

There is still a constant red light. The fan stays on at a very low speed. No line indicators LEDs flash.

What does #2 above mean in reference to calibration being low or high?

Just one more thing for now: I found a guide on this forum that shows how to do a hard reset. What should this actually result in?

Thank you for any help.
Looks like Leviton bought NSI and they have pretty good tech support to call.
 
I've had reasonably good luck with Leviton/NSI tech support. They tend to want to call you back in X amount of time because the support people have calls stacked up. It has been my experience that they do call back, but you really need to be near the dimmers so you can actually follow their directions and discuss the results with them. They are knowledgeable about these dimming products, as they should be, and they will take a parts order (or at least used to). They do offer expedited service for a surcharge if you need to send the unit in and get it back quickly.
Are all three dimmer packs having the same issue?
As previously mentioned, if the fan fails the self-test at startup, you might have 3 fans that have gone bad.
I would remove one of the fans and hook it up to a power supply of whatever voltage they are supposed to run on (as marked on the fan). If the fan then runs smoothly at full speed, the problem is likely the temperature sensing circuit itself.
 
Something I forgot to mention is that these dimmers have been left on for who knows how long, guessing for years. When my wife first started there she found a note on the rack starting "do not turn off".
I will get the secretly hidden key from maintainance to the breaker box, shut down, then see what happens when I restart. Let you know as soon as I can. The school has a 4 day week and is 35 miles out.
 
Thank you FMEng, Ben Stiegler, and microstar.
I am going to perform a "maintenance event" the next time I can get to my wife's school. Having worked since 1978 in music stores with a Certification in Consumer Electronics, I have experience in servicing most every type of music related equipment.
With these NSI DDS8600 dimmers I will start with internal cleaning, checking for ventilation blockage, and then perform a startup (one at a time) so as to observe the built-in self check described by FMEng, then post my findings here.
 
I found Leviton's support page which had a choice to call and wait on the phone or enter your phone number and be called back. The call back came only a few minutes later👍.

He was very helpful, sent me instructions, a photo of the PC board with notation of the calibration potentiometer location, and answered all my questions while we were on the phone.

Thank you for suggesting to contact Leviton.
 
I was mistaken, we have four NSI DDS8600 dimmers. Two of them work fine. One shows no life at all, and the fourth one has the problem I described in my first post. I have learned that the "NSI MULTIPLEX" does not work in this forth dimmer and when it was included in the parallel hook up with our NSI MC7524 Lighting Console, was preventing any control of the lights.
So, now we have the twelve over head stage lights plugged into one working dimmer (two per channel) and the six (I'm not sure what they are called, house to stage lights?) plugged into the other dimmer. Now the lighting console works and the students are having a blast setting scenes for their play which is coming up soon.
The head maintenance man told me that the school was hit by lightning some time ago. I am going to open the dead dimmer and check the fuses, maybe we'll get lucky :dice:
 
You might find the multiplex receiver chips socketed, when the rest are not. If so, you might replace them if you don't find anything else wrong. They were connected to an antenna during the lightning strike.
 

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