Converter buzzing when fan is off

[perkc2]

Hello all,

Our converter is making a buzzing noise when the fan is not running. This is when we are plugged into shore power. When I turn on the lights the buzzing usually subsides. I had it looked at by an RV repair guy who thought it was just a loose wire in the inverter, but evidently this was not the cause. Our battery does recharge fine. Any ideas? I’m wondering if it’s just going bad. We have a 2010 Flagstaff 27BESS.

Thanks!

[PaulJ2]

Many times it is the transformer coil assembly loose and vibrating against its core. Usually epoxied to prevent this.

[westend]

If the buzzing is very annoying, you can try to tighten all the bolts attaching the transformer to the converter frame. Sometimes, that will eliminate a resonant "hum".

[camperdave]

My pd9160a has buzzed at no load since new. Turn on a light and it's silent.

[rockhillmanor]

That buzzing was the first sign of my converter dying.

Only no one could figure it out. they would test its output by putting the meter on and pulling it off as soon as it hit the correct output.

REAL long story short. AC stopped working, then the fridge and THEN I started smelling sulphur.

Took 3 repair guys and finally the third guy figured it out.

He put the meter on the converter and "left it there". That thing climbed so high I still can't believe it didn't explode.

It was so high it was boiling my coach battery. When we pulled it out one of the capacitors looked like someone shot it with a 10 gauge!! How it even worked was beyond me. It could still turn on but couldn't regulate it self.

I.E. buzzing converter bad. :C

[deltabravo]

Artum Snowbird wrote:
If you were full of magnetism you might buzz too. But seriously, it's a transformer buzz. As they age, the irons might get a bit loose, and they buzz when they used to just hum.

Yep. Buzz and/or hum is normal.

That's what transformers do, is hum, because they don't know the words. LOL

[afidel]

Sounds like transformer ringing, not always a problem but if it didn't have this behavior before it likely is a sign that something changed which in a solid state system is usually a signal that something is going to fail. Based on the age my bet would be that an electrolytic filter capacitor is dying due to age. The good news is that replacement converters aren't all that expensive (a good electronic tech probably could find the bad cap and replace it but it would cost nearly as much in diagnostic time costs as it would to buy a new converter).

[Artum_Snowbird]

If you were full of magnetism you might buzz too. But seriously, it's a transformer buzz. As they age, the irons might get a bit loose, and they buzz when they used to just hum.

Experiment a bit, take the breaker cover off and have a listen when you are down low, then turn on as many silent loads as you have.. lights. See if it buzzes more. If you have LED lights you are only producing a couple amps, but if you have incandescent you have an amp per light bulb.

Nothing to worry about though. If you are really curious, get a laser thermometer and record the lights and the temperature, then see if it changes in a year or two.

While you are doing this, tighten all the screws on the 12 volt positive and negative terminals, especially the big wires that go from the converter to the battery. That can be a source of problems too.