Very loud noises when lights are on

[Jacspill]

Moved from here.. Very loud banging noises when lights turn on

I'm having the same issues and adding felt pads to the cover eliminated the loud banging noise. I'm still uncertain about the transformer buzzing when the light is on. I find it loud and quite annoying since it can be heard from the pool.
Here is a video comparing the sound level of the intelliflow pump (running at 1800rpm) with the sound level of the transformer, is that kind of sound level expected from the transformer? The Pentair 5G light it turned on using the Pentair Intellibrite controller and you can hear the characteristic on/off cycles at the beginning of the video.
PX300 transformer noise

 

[PoolGate]

That does seem pretty loud but it says it has a low voltage transformer in it. Transformers do hum but that seems excessive. My Jandy light makes no sound at all but there is no transformer. It does go through the clicks to change the color but it is just the relay clicking on/off. Then total silence.

 

[Jacspill]

yes, transformer, my light is 12V, I'll contact intermatic for their opinion on the noise

 

[Desert Dog]

I suspect the transformer is bad or something loose. I have one. It clicks when it turns on but does not make noise otherwise.

 

[Jacspill]

I contacted Intermatic and should be able to get a replacement, we'll see

 

[Jacspill]

So, I returned my Intermatic transformer under warranty and got the Pentair transformer instead. It solved the issue. The Pentair transformer is much quieter, there is still a faint buzz but nothing like what the Intermatic did.