NMEA 2000/ Airmar DST 810 help

[GILow]

Originally Posted by asimegusta

Hello fellow DST810 sufferers,
I have just read through the thread and must say my experience has been the same as others.
My second DST810 just shorted out after 8 days. It was a replacement sent by Furuno for my first DST810 which failed just a few hours after install in February 2024.

Now, the second DST810 first lost depth measurement , while speed and temperature still displayed. Then 15 minutes later the NMEA2000 fuse blew and the display went blank.
We confirmed the issue by disconnecting everything except the DST810 which blew another fuse. We disconnected the DST810 and the NMEA2000 network and the display work perfectly.

Back on the phone tomorrow about getting a second replacement
The problem seems to continue to exist in 2024 unless I was shipped older units.

They reseller also tried to put suspicion on my NMEA2000 network setup. My network consists of just the DST810, the wind tranducer and an Fi70 display, all brand new installed in February 2024.
This second failed DST810 has definitely shaken my confidence in the reliability of the DST810. Can't sail without a depth sounder around here in Southwest Florida.

I believe there’s a manufacture date stamped on the device. Can you find that info?

[GILow]

Originally Posted by asimegusta

…


They reseller also tried to put suspicion on my NMEA2000 network setup. My network consists of just the DST810, the wind tranducer and an Fi70 display, all brand new installed in February 2024.
This second failed DST810 has definitely shaken my confidence in the reliability of the DST810. Can't sail without a depth sounder around here in Southwest Florida.

Can you monitor the voltage on the bus? The blown fuse does suggest over voltage and the Airmar guys did firmly point out that there are voltage standards for the bus that need to be adhered to,

Their claim was that the original mosfets were more tolerant and that the “faulty” batch were simply less tolerant of over voltage conditions.

They certainly convinced me that my home brew setup would be an advantage as I’d have control over the voltage supply at all points by using appropriate voltage regulator supply chips.

[kaz911]

Originally Posted by GILow

Can you monitor the voltage on the bus? The blown fuse does suggest over voltage and the Airmar guys did firmly point out that there are voltage standards for the bus that need to be adhered to,

Their claim was that the original mosfets were more tolerant and that the “faulty” batch were simply less tolerant of over voltage conditions.

They certainly convinced me that my home brew setup would be an advantage as I’d have control over the voltage supply at all points by using appropriate voltage regulator supply chips.

Over-voltage does not normally blow a fuse unless we are talking exceptional high voltages causing other issues - it is the amps that blows it.

Often fuses blow from "short circuits" which can happen when a mosfet blows as it pulls a lot of amps when shorted.

Or you could simply overload your fuse with consumption in A's - that will blow it too..

[kaz911]

Originally Posted by GILow

I believe there’s a manufacture date stamped on the device. Can you find that info?

Yes the manufacture date would be great to get! Always on the label on Airmar products!

[Fuss]

Did anyone pull one apart and look inside?

[kaz911]

Originally Posted by Fuss

Did anyone pull one apart and look inside?

as far as I remember the whole tube is "potted" (filled with silicone or epoxy) - so it would require a LOT of work to check components inside. But it is a good 20 years ago I opened one of the previous ones up..

[GILow]

Originally Posted by kaz911

Over-voltage does not normally blow a fuse unless we are talking exceptional high voltages causing other issues - it is the amps that blows it.

Often fuses blow from "short circuits" which can happen when a mosfet blows as it pulls a lot of amps when shorted.

Or you could simply overload your fuse with consumption in A's - that will blow it too..

V = IR

Over voltage CAN blow a fuse if the resistance is constant.

[cram]

Is the drain/-shield wire connected to anything (it's part of the 12v pigtail).

Did you try swapping out the backbone or node wire going to the transducer?

Edit.... really old post..... forget about it!

[Fuss]

I just bought a broken dst810 with a new through hull and blanking plug.
I tested it and all is working, airmar cast, temp, speed, connects perfectly to the iphone app. But depth is not working on land. I tried a bucket of water, I tried listening for clicks, I tried a steel plate. I am sure now that depth it is not working at all.
I wonder how this can happen. I assume that spikes or high voltage would kill more than just the depth. Others have said that the temp goes first as a symptom followed a few months later by depth.


you have to keep the nmea2000 running around 12.5v and no spikes. My old instruments 0183 nmea were completely reliable once I put them behind a 12v converter which stabilised the voltage.



anyone have the same experience with the dst810 that all is working except depth?

[crosswire]

I installed a DST810 in May 2023 and it worked fine until April this year when the temp reading started to read much higher than actual, about double. Two weeks ago, the temp display went to three bars, the speed and depth have been working OK. I guess I should expect the depth and speed to fail soon. My network is powered in two places, the NMEA2000 backbone and the Smart Pilot. As others have indicated, none of the other devices have been affected.

[kaz911]

Originally Posted by crosswire

I installed a DST810 in May 2023 and it worked fine until April this year when the temp reading started to read much higher than actual, about double. Two weeks ago, the temp display went to three bars, the speed and depth have been working OK. I guess I should expect the depth and speed to fail soon. My network is powered in two places, the NMEA2000 backbone and the Smart Pilot. As others have indicated, none of the other devices have been affected.

N2k networks should not be powered from multiple sources at the same time unless the network parts are separated with an active N2k bridge device. (YachtDevices NMEA Bridge YDNB-07 or CZone/Bep Marine N2K Network Bridge Interface)

The only exception is when two segments is "split" like some N2k power feed T's are - so same power source have "2 power cables" individually fused. I have the Actisense QNB-1 that supplies "both sides" of the backbone individually - each segment with a 4A fuse.

The power output from your SmartPilot is voltage controlled by the SmartPilot and not feed directly from your 12v network (as it works on 24v as well). So voltage might be different to your "direct from battery" voltage.

I have 2 N2k backbones - one is "always on" for monitoring. The other is instrument displays and items only in use when under way. They are combined using the CZone Bridge.

/k

[crosswire]

Thanks Kaz, I did try using only the Smart Pilot power for the N2000 network and still got the low voltage alarms.

Curiously enough, although I purchased the 810 in May, 2022, not from EBAY, the date on the unit is Mar, 2017, which predates the pandemic supply chain issue.

[kaz911]

Originally Posted by crosswire

Thanks Kaz, I did try using only the Smart Pilot power for the N2000 network and still got the low voltage alarms.

Curiously enough, although I purchased the 810 in May, 2022, not from EBAY, the date on the unit is Mar, 2017, which predates the pandemic supply chain issue.

Your issue with temp sensor is not the "standard" DST810 pandemic supply chain issue. To me it sounds like either manufacturing issue (assembly) - lift out issue (remember to remove them before lift out) - or impact issue.

If plastic has gotten a small crack it can slowly cause all kinds of issues. Temp and depth sensors are in the lower part so first to go. Where with the pandemic issue everything went.

So it sounds more like a "oh s*it happens" things. Not like "our production stock is full of manure based products"...

[crosswire]

I have a full keel boat and the sensor is tucked in under the turn of the bilge so that straps cannot get to it. I will check for carefully for cracks. I have not seen any during routine cleaning of the head. Another boat gremlin.
Thanks

[kaz911]

Originally Posted by crosswire

I have a full keel boat and the sensor is tucked in under the turn of the bilge so that straps cannot get to it. I will check for carefully for cracks. I have not seen any during routine cleaning of the head. Another boat gremlin.
Thanks

The cracks can be tiny.. But if it is well protected it might just be factory assembly issue - no production is 100%.

I did one once where they thought they had hit a log or other submerged object - on that it was obvious as paddle holder had a crack on one side. But it still "kind of worked (speed was not right) " until it just died.

But DST810 are made for quick and easy removal.. with N2k it is an easy job. There are plenty of old DST810's on eBay - but don't by the pandemic year ones...

For your low voltage alarms - check your supply power. I think you can probably power all of it from the smart pilot - and measure while in use. If your voltmeter has a min/max or logging function - that is very helpful.

Fluke 287 Multimeter (expensive) can log - and will force log "exceptional" voltage moves. So even if you measure in 1 minute intervals it will catch spikes or drops in voltage in between the "intervals". There are probably other instruments that will but I kind of got stuck on the 287/289's.