Dimmer pack making loud consistent buzz

[RWilson]

Hello,

I have a set of CD 80 dimmer packs that are hard wired into a school. They were recently converted from AMX to DMX. I noticed that they were all right, noise wise, and then there was a solar panel installed above the theatre. Now this may have nothing to do with it, because I don't really understand it, but since then the packs make a very loud high pitched steady buzz that does not change regardless of dimming levels. I only mention the solar panel because it was a significant electrical project to the building overall, and I am wondering if there is something connected to the noise. The dimmers function fine, there is no problem with their operation, but I'm concerned about what the noise means. Any help would be much appreciated.

 

[DavidNorth]

How many packs do you have?

Are they packs or larger racks?

Do all of them make noise?

My initial guess is fans either really dirty or going bad but I think we are going to need a lot more detail first. Any additional desriptions of the noise, when it appears or disappears, if there are problems with other gear on site, if any other installation changes were made, would all help.

Thanks,
David

 

[JD]

Are you sure of the source of the noise? Sometimes noises can project that are created elsewhere, or follow a metallic path from the source to where you are hearing it.

Now, here is why I am saying this:
1) Dimmer buzz noises usually track with dimmer levels.
2) Solar units are DC so to use the power, it must be converted to AC, meaning there is a big new inverter somewhere, and they can be noisy. Since the install is above the theater, and coincides with the new noise, one would think there -may- be a connection.

 

[phenry]

I have never heard a pack make a steady buzz. Dimmer hum of course, but that would change with load. My first step would be to power down the packs when possible to simply see if the noise stops. if it does, then as David suggests, check the fans first.

 

[BillConnerFASTC]

It's possible that a conduit or other path to the dimmer rack makes it sound like the dimmer rack when in fact the noise source is located elsewhere, but de-powering the dimmers as has been suggested is the first and easiest diagnostic.