[TG] [TG11] Sounder Supply Voltage Too Low

[MarkPOrge]

I have the same problem with the A128 I just added last summer. The A128 at the helm functions fine, but I get the error after about 5 minutes of use. Voltage is good, I'll look for an update but according to the site V19.03 was out in April 2017, nothing new since?

The only difference is a new (separate) transducer for the front head. It is the A80351 and the one on the transom is the older version A80270. Not sure if that matters, I was going to try a new transducer or I could always network but I hope to avoid unnecessary costs and/or re-wiring.

Are we the only two reported cases of this?

Mark

[Tom - Raymarine - Moderator]

Hello Mark,

Personally I'm not aware of any other cases, but that's not to say that other people aren't seeing it and if anyone else is I would be interested to hear about it.

Re. supply voltage: it's surprisingly difficult to say for sure that voltage is good:

• Voltage at the battery or at the distribution panel is not going to be quite the same as product supply voltage (there's always some degree of drop along the run of cable and connections) and if there's a bad link in the chain somewhere then that voltage drop can be significant
• Voltage measured at the display end of the cable is no-load: if there's a high-resistance connection somewhere (and this is a boat: high-resistance connections are very likely) then you will see a very different and much higher voltage with no load than with a few amps being drawn through the cable.
• A multimeter or distribution panel indicator will only ever show an average voltage, they will give no idea of the stability of the supply or the lowest voltage that will be reached when there are dips due to current being drawn by other products being powered through the same distribution system. Multimeters only measure voltage a few times a second, but I've seen voltage dips as short as 10 milliseconds cause product brown-out reboots. You can only see that kind of voltage dip on an oscilloscope, which is why we encourage all technical dealers to have one in their toolkit.
  

What I tell our technical dealers is that unless they've measured the supply on the end of the product's supply cable with an oscilloscope with a full operating load applied (everything on the boat on, in full at-sea conditions), then they can't be absolutely positive that the supply is good. Battery capacity and charge-state have very little to do with it: trust me, I know from long and bitter experience. I've seen product supply voltage dip below 9V on a new, 50' powerboat with 27V at the batteries.

I don't think that changing between equivalent transducers would be likely to affect this, unless the new transducer were faulty and had a much lower impedance (and so drew much more current) than the old one. The two part numbers you mention have the same nominal performance, and the same Sense resistance which is what the display uses to detect whether it's there or not. There should be no operational difference between them. Changing to a different type of transducer (e.g., on a different model display, changing from 600W to 1kW) could draw more current and prompt an alarm if the supply were marginal.

Regards,
Tom

[Johnrielly]

I am getting this issue on my A128. Is there a way to just get rid of the message box that covera half my screen? The finder works just fine allday but has the annoying grey voltage suppy low error in my way.

[Tom - Raymarine - Moderator]

Hello John,

There's no adjustable threshold for the alarm to be triggered: the warning is being presented because the display is measuring a supply voltage that is too low for reliable sounder operation. Either that's a genuine and problematic low voltage (e.g. a high-resistance connection somewhere in your power cabling/connections), or it's a problem with the measurement inside the display. If you believe the latter is the case then you should get the display checked by a Raymarine service centre.

Regards,
Tom