[ReelMagic]

When running my 2003 38 Open with the generator "OFF" my SIMRAD IS15 digital dept finder tracks the depth quite well. When I turn my ONAN generator "ON" the depth finder has problems tracking depth and looses track quite often. It may loose track for several seconds or even several minutes. The transducer and generator are approx. 5' from each other in the bilge....Has anyone experienced this problem and if so have you found a solution... Believe it has something to do with "electrical noise" created when the generator is "ON"...

[Uhehner]

Put a digital meter set to a low AC scale ( less than 10 volts ) across the DC bus feeding the Simrad. Start the generator and see if you are getting AC noise on the DC line when your generator is running. I would then suspect the battery charger. Try turning it off.
Capt. George

[ReelMagic]

thanks. will give it a try

[ReelMagic]

Fixed..... Finally found the source of electrical interference with my SIMRAD digital depth finder causing it to lose track.... Behind the steering station where the transducer cable is connected to the display unit the transducer cable shield ends. This is where the 4 wires (NMEA 183 pair, and the 12 volt power supply/return) are located and the installer placed a wire wrap around all 4 wires (NMEA signal wires NOT shielded from the 12 vdc power/supply). Removed the wire wrap and separated the 12 vdc power/return & NMEA 183 signal wires as far as the wires allowed ( approx 3") and it looks like the interference causing the depth finder to lose track is gone.....Confirmed the fix over the past few days running the boat with & without the generator running.. The SIMRAD hasn't lost track once since separating the wires.... Interference must have been the close proximity of the NMEA 183 signal and the 12 vdc power/return wires......