Audio whine when water heater is on

[brad1]

I've got a 2009 International that came installed with a Sony MEX DV2000 a/v system. There is an annoying high pitched whine that occurs intermittently. I believe I have isolated the appearance of the whine to the use of the water heater.

Does anyone have any ideas what could be going on here? I'm open to suggestions for additional trouble shooting and or potential fixes. My guess that there is some grounding issue doesn't get me far.

BTW, I'm currently ensconced at Dance Country RV Park in McCloud, California, where the sky is overcast and threatening rain. We're planning to fish the Upper Sacramento River if we ever get done with breakfast and lounging around. Quality note about the park: very nice spot, and well kept, but I wish the showers had a little more pressure.

[snake]

Any electronic circuit board can create radio frequency interference, you might experiment with using a ferrite suppressor on the 12v wire to the water heater circuit board, one of those little things that you often see on electronic cables.

Try a google search for "RF interference" or "ferrite suppressor"

[brad1]

Thanks snake. That makes sense and doesn't sound either too difficult or too hard to back out of if it doesn't work. I'll give it a try.

B

[barts]

Does the whine occur only when using the radio? Or when using both radio and CD player functions?

In addition to ferrite beads, small tantalum (e.g. fast ) capacitors going immediately to ground from the power
input wire on both the Sony and water heater will help.
These will bypass high frequencies to ground; the ferrite beads block them as well and the effect is cumulative.

I'm surprised that the Sony is susceptible to this; a car is a very noisy place wrt RF, with alternators, small DC motors (windshield wipers, power seats/windows), etc. This is a common problem, and there are lots of hits on google for
"car audio noise filter" and the like. Any place selling better car audio gear will have stuff for this if you don't want to roll your own.

Lots to read... out there.


- Bart