Raymarine E-120 Chartplotter Issue

Raymarine E-120 chartplotterBack at the end of April, I mentioned removing our Raymarine E-120 multi-function chartplotter instrument to return to manufacturer for a repair. The problem is that the back-lighting has been randomly “flashing” to full brightness and back to dark when running at night. This has the very annoying effect of destroying your night vision while at the helm.

When I reported this at the Raymarine online tech support, they suggested it could be a low-voltage situation. But, they suggested sending it in. After paying hefty shipping and insurance fees I sent it off before my backpacking trip. I expected they would fix the problem and ship it back.

Last week, they called and said their tests showed the E-120 is working fine. They recommended a voltage isolator/converter to basically control against surges or voltage drops due to other electrical equipment in my system. After discovering the unit they recommended costs several hundred dollars (this is what they recommended), I wondered if this is an isolated incident or a problem with our electrical system. E-mails to other St. Francis 50 owners, and the manufacturer confirmed they have all seen this annoying problem with the E-120. So, I did some Googling and discovered several other E-120 owners on many different boats have reported the problem. The most common factor seems to be that when the E-120 backlight is in low-light mode (at night), and the alternator regulators are charging the batteries, you get the flashing on the E-120.

The E-120 specs say it can handle 10.2 to 30 volts of power. But, I suspect the backlight system is more sensitive. I’m curious whether there are cheaper voltage isolators which might solve the problem. Time to do more digging… Ahh, the fun process of diagnosis and learning the quirks a complex boating system.

[UPDATE: I found an inexpensive DC-DC converter (it basically regulates the variable power from the boat to a rock-solid 12V at up to 4.2 A). Here’s the link – it cost $27. This solved our problem and the E-120 has never had the problem again. I would recommend this solution for other electronics sensitive to power.]

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7 Responses to Raymarine E-120 Chartplotter Issue

  1. John Alonso says:

    Have you had any luck in resolving the problem? Did you try a voltage isolator yet? I have a similar issue on our boat. Thx

  2. Frank Taylor says:

    @John: I was told to try getting a less expensive voltage converter like this:
    Unfortunately, it has to take the slow boat from China (literally). Earliest they said they could get it was July 28th. I haven’t ordered it yet, hoping I could find one sooner.

  3. Leonard says:

    Please let us know if voltage isolator solve your problem, coz I have exact same problem.

  4. Frank Taylor says:

    I meant to follow up here and say the part I ordered in the comment above works perfectly! And, it was the cheapest option I could find.

  5. Sandy Hollis says:


    Thanks for providing this information. We’ve been experiencing this problem on a 47 Leopard (owner’s version) we just purchased in April, 2011. We sent both E120 units into Raymarine for this issue and another problem. Raymarine indicated the problem should be fixed. One problem was fixed, however, the problem you described above was not resolved. We have just purchased the SD-50A-12 which you recommended, and hopefully, it was solve the problem. Any suggestions regarding installation? Is it something we can install ourselves? Your advice would be greatly appreciated. Sandy

    • Frank Taylor says:

      Hi Sandy, the installation was pretty easy. On our boat, they chose to use the short cable provided by Ray Marine for the E-120 and extend the cable to our power source. I simply un-connected the two wires and put the power regulator between the two and screwed into a nearby wall. Haven’t had a problem with it since!

  6. Sandy Hollis says:


    Thanks again for the information. We did order the part and just received it. It looks pretty straight forward (i.e. input/input, output/output), however, what’s throwing me is the V Adj twist knob to the right of the input/output connectors. I would assume it’s for adjusting voltage. We didn’t receive a manual with our equipment. Did you? Would you happen to know how to use this knob? Any help would be greatly appreciated. Thanks so very much. Sandy

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