Panel “Buzzing”

So my panel started making an obnoxiously loud buzzing noise and I didn’t do anything to it to make it happen. When I disconnect my AC power, the batteries do not kick in, but they are charged and the charger still works. I know it’s not the transformer, it is something on the board. Any ideas, everything else, NACs, IDCs, Relays, are working just fine.



Please help.


First off, we need to know what panel is producing said noise, it may/will make a difference due to the differences in circuitry. I am assuming that the buzzing you are talking about is not the on-board piezo, but more like a loud AC hum. More information about the issue will help with a diagnosis, and hopefully a solution to the problem.

I’m stupid,



It’s an MS5210UD

Can you find the origin of the buzzing, is it from the main board? If you can figure out what component is emitting this sound, that may help.

It seems to be on the board. One of those blue/purple large metal pieces that sticks out. Usually a square shape (heat sinks?)


I have never seen or heard of a blue or purple heat sink, but I know excessive heat can make them look pretty like that. Unless it is painted, it may be overheating. If you want to check, don’t touch it, it WILL hurt, trust me. How loud would you say this buzzing is, is it comparable to the on-board piezo or more like a NA. I know you said you didn’t do anything to cause this, but may you have accidentally connected the batteries while the panel isn’t connected to AC? Not saying that you did, but that tends to fry something, I have seen panels out in the field that got toasted by this mistake.

Nope i never did that with my batteries. Cute story, i disconnected everything last night (NAC’s IDC,s, Batteries), and this morning my garage smelled of burning electrical stuff and i was soooo happy to find out a component blew up on the board. Everything is still fine tho

Do you know what component blew up?

It was a small square with 3 leads coming out of it.

It probably is a transistor or dual diode. Both have 3 leads. Is there enough left to read the numbers on it?

Nope. It’s completely destroyed lol, it was connected to auxiliary power which I don’t use anyways, so everything is fine now!