humming noise on circuit board

[Matt]

I recently relocated my two house batteries to the other side of the boat and in doing so ran the negative back to the common ground (that the starting battery is already hooked to on the engine) rather than to the starting battery (as it had been). I'm now noticing a humming noise only when I turn on the dc power on the circuit board (not when i turn on the battery selector switch). Is my problem associated with using this common ground (ie, should i run the ground on the house batteries back to the ground on the starting battery) or is it likely just a loose wire at the circuit board?Thanks for any help. Matt

 

[Jim Ewing]

Hummmmm....

Matt,DC really should not hum. Did you change any other wiring at the same time (I thinking battery charger here particularly) that may have resulted in an AC source ending up on the same ground circuit? Does the hum sound like 60Hz AC (the noise your inverter makes if you have one)? Try turning off the AC side of the panel to see if the noise goes away.Jimh 37.5 "Esmeral"

 

[R.W.Landau]

Sounds like a loose connection to me.

r.w.landau