Power supply for GL 3000 scary noise

[Lisa Lane-Collins]

Sounds like a wet powerline, that is to say, it's buzzing. This sound does not carry through to the speakers, it's isolated to the power supply but I can't remember if it was ever that noisey before.

Is this normal or sign that power supply is dying?

 

[John Roberts]

Re: Power supply for GL 3000 scary noise

Don't know what a wet power line sounds like.

Loose laminations and low mains voltage can cause audible hum from eddy currents vibrating the metal plates.

May be evidence of higher than usual load, low mains voltage, or may be nothing.

JR

 

[Alan Sledzieski]

Re: Power supply for GL 3000 scary noise

Don't know what a wet power line sounds like.


JR

Welcome to my world.

Sound of Rain on Power Lines near Radisson Quebec - YouTube

 

[Lisa Lane-Collins]

Re: Power supply for GL 3000 scary noise

Nice vid. Doesn't quite sound That bad, but still, a definite electricity sound.

Here's hoping it's nothing. Spose if it dies I'll cross that bridge then.

 

[Alan Sledzieski]

Re: Power supply for GL 3000 scary noise

You mean more like this sound.

500kV Power line noise - YouTube

 

[Greg Cameron]

Re: Power supply for GL 3000 scary noise

I wonder if the mounting screws for the transformer have come loose and are allowing the normal vibration to create a buzz. If it's really noticeable, you might want to have a bench tech take a look. PSUs were not one of A&H's strong suites when it came to reliability on their smaller analog desks. I've had a couple of failures of the RPS9 for my GL2200. But the issue was different than yours. I had voltage regulator IC failures which dumped a lot of noise into the board.

 

[Scott Helmke]

Re: Power supply for GL 3000 scary noise

Are you sure it's not the fan going bad?

Certain Soundcraft power supplies tend to have the bridge rectifiers go bad, and in the weeks before they finally blow the transformer tends to start humming.

 

[Lisa Lane-Collins]

Re: Power supply for GL 3000 scary noise

If i had to be my own bench tech, how do i test the tranformer, fan etc?

 

[Alan Sledzieski]

Re: Power supply for GL 3000 scary noise

If i had to be my own bench tech, how do i test the tranformer, fan etc?

As far as the fan, is it spinning? The transformer, check for loose screws that hold it down. The fan can possibly just not be spinning, allowing things to get hot, and then hum more.

 

[Alan Sledzieski]

Re: Power supply for GL 3000 scary noise

I had a gl2200 that started humming, it was a internal power supply, it turned out to be the fan bearings going bad, I opened it up turned it on and heard it from the fan instantly

 

[Helge A. Bentsen]

Re: Power supply for GL 3000 scary noise

I had problems with bearing noise from the fan in an old RCF amp. Peeled off the bearing cover and used some synthetic gun oil on it. Lasted for years afterwards.