Pulsing dimmers

[Nathan RAC]

we have really old, analog dimmers and they recently started pulsing from about 1%-10%. Even with no DMX input. I believe it could be the DMX to analog converter (elation multi-data/pak) as the dimmers stay at 0 when this unit is turned off. Can anyone help with this?

 

[Nathan RAC]

link to the DMX - Analog converter http://www.elationlighting.com/ProductDetails.aspx?ItemNumber=1099&MainId=1&Category=ZDiscontinued

 

[Harley Morgan]

When you say no DMX input, you mean your console is off, or you unplugged the DMX cable?

If you unplug the converter from the dimmers, does the issue remain?

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[TheaterEd]

Are you using DMX cable or just old sound cables?

 

[Nathan RAC]

DMX cable is unplugged and I have not unplugged the dimmers from the convertor.

this system has been working for the past few years and only started doing this in the past week

 

[Harley Morgan]

The elation also offers different voltage settings for the output. Make sure that setting hasn't been changed. I would assume this should be set to 10V, burn may be different depending on your dimmers.

Is it possible the converter was accidentally put into chase mode?

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[Nathan RAC]

voltage is set to 10V, its possible that its locked in chase mode. Do you know if there is a factory reset?

 

[Harley Morgan]

There is no factory reset in the manual. If it's in chase mode, the display would say chas.

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[Harley Morgan]

But you can hit the chase button to see if it changes anything.

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[Nathan RAC]

okay so its not in chase mode, and when i enter chase mode the same thing happens

 

[Harley Morgan]

In chase mode, they still pulse at low intensity, or chasing at full intensity? In either case, I'm leaning towards your initial thought of the converter going bad.

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[Nathan RAC]

they still pulse in low intensity, exactly the same when its in DMX mode. Could it be something simple as dust?

 

[Nathan RAC]

okay ya, just opened it up and its pristine, no dust.

 

[Harley Morgan]

When it comes to troubleshooting, you never know. If there is enough dust to be worried, then you should probably go through and clean the dimmers, and the converter. It's possible something overheated and got fried. In truth, this issue could be many things. Bad cable, ground loop, bad converter, or cable polarity.

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[Harley Morgan]

Do the dimmers still behave when DMX is present and intensities are turned up?

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[FMEng]

If you unplug the converter from the dimmers, and the dimmers still act up, then the culprit is the dimmers. If the system only acts up when the converter is connected, then it is the converter. You could also take a voltmeter and check the analog outputs to see if they go from 10 V down to 0 V or have AC noise on them.

 

[Floobydust]

Ive had excellent results from these D/A converters: http://www.northlightdmx.com/dmx512decoder.htm

 

[microstar]

If you isolate it to the converter, it is possible one or more of the electrolytic capacitors in the power supply have gone bad and the ripple is providing the control signal/dimmer pulsing. Take a meter and see if the pulsing is visible on one of the converter output channels.
Carefully examine the capacitors for a domed (pushed up) top instead of the normal flat top. If so, they should be replaced.

 

[Nathan RAC]

with the convertor unplugged from the dimmers, the dimmers stay at 0, so its the convertor box itself. I will check the capacitors, and check the the analog outputs with a volt meter to see exactly whats going on and report back later with my findings. Thanks for all of the replies and suggestions.

 

[Nathan RAC]

Alright, opened it back up again and found that 2 out of 4 of the capacitors are blown. They've domed up and have a smell to them.