Done a resent update?

 What type of power do you have inboard, O/B?

Sorry, should have mentioned that we have an outboard and transducer is transom mounted.  2010 200hp yamaha 4 stroke.

Strange as it only started doing it fairly recently - had over 18 months of no problems at all

If it was me,

I would start with the checking all connections to trany (not improved)
then remove trany and put on a pole (duct tape) over the side of the boat get clean water and check readings
Without sounding like a nitwit,the unit is set up with the right trany logged into the main software YES?
Screens like that generally mean lost of bottom or dirty water (I.E bubbles etc)
ID sticker should be on the cable of the Trany.

From my experience this generally seems to be a turbulence issue (in that the reversing is the cause). Mine does it now and then and a power reboot sorts it out.

That being said was on a mates boat a week ago with HDS7 and same thing happened but power reboot did not sort it this time. Tranny was not reachable from inside the boat and I wasn't going over the side to have a look where we were.

Had structure scan so we just used downscan to get depth (trolling for tuna - so not a huge issue at the time but a pain nether the less), don't know if its sorted since. I know the unit his unit is set up properly - I did it myself.
Unsure why the reboot did not sort it.

might be a random thought here guys mabe when loading boat on trailer could of been some oil in water from a 2 strke motor coated the transducer and when you reverse it is holding bubbles on transducer which is taking awhile to clear just a thought clean the trasducer and see what happens ??

 Ive had the same problem on my hds 10 im running a b164 1 kw and a tranny mount 83/200

when it happened to me at the time i was running the b164 i changed over to the 83/200 changed the settings for it and still couldnt get it to work for the whole day changed back and forward on the trannys  so its def not tranny problems its in the unit and from what i hear its very common 

i ended up buying a furuno 587 afew months back and using the b164 and never had a problem with it 

Each time it happens I give the transducer a good check over and thorough clean - doesn't make a difference unfortunately.  I feel as though i've tried almost everything under the sun to get it back online, but time is the only proven solution!

Interesting your mate had a similar issue Paul, albeit just the once?  I wonder if transducers just start to give up over time?  Perhaps taking longer and longer to sort themselves back out after an issue such as turbulence?

Note knowing how it's wired up,try wiring it direct to a power source and not through the ignition system.(Clean power supply not connected to boat)
I would see if I could borrow a trany from a loc boat dealer before forking out for new one.

 Is that O/B cable shift or electric ?

Not too sure about cable/electric shift sorry.  Assuming it would be cable, but that is just a guess. I will have a look at the setup and try wiring independently to see if it could be caused by some sort of electrical interference perhaps.

Streaker - your experience is what I was a bit worried about, that it would be the unit itself rather than just the transducer or some other cheaper fix.  Will hopefully be able to test out different transducer like you could and see what happens.  If no luck, will be an excuse to get a new Furuno with 1kW transducer...

exhaust bubbles getting thrown backwards with reverse gear along with prop wash breaking tranny beam i reckon

and after that I found that the selected transducer had gone to "generic". Guess you've checked since doing the software upgrade?

 When i had this problem i googled about it and from what came up seems like its a common problem

try googling it 

now i just run the hds 10 for mapping and my engine data and use the furuno 587 for sounding 

 Maybe check your alternator output @ idle

most of the gadgets nowadays are happy to function on multivoltages,but they don't tolerate spikes in voltage

if your shifting from F thru N toR maybe Yamaha may cut the ignition for a millisecond to assist smooth shift?

this may effect the output voltage to the unit & may be enough to throw the sounder into Bit of disarray & give you this issue

 Best to have dedicated power supply independant of start battery to alleviate this issue

Will be standing by for the final prognosis .

Thanks to everyone for their suggestions and troubleshooting help.  I'll be sure to update this thread if/when i get a solution.

I checked all the wiring last night - it was a bit messy, but the unit is in fact wired directly to the power source, independent of start battery and other accessories.  The negative lead from the unit had several very low gauge wires 'joined' (with electrical tape) before attaching to the power source, so I cleaned this up and joined it properly.  Not sure if this would make any difference, but worth fixing up.

I'd also previously talked to Lowrance over the phone - neither of the technicians had heard of this particular issue before and didn't have too many ideas on how to rectify it.  One assumed that the transducer was to blame.  He suggested attaching a different HDS head unit to our boat to see if it does the same thing with our transducer, or attaching my HDS head unit to a different boat to see if it does the same thing with their transducer.  Could then rule one of the components out.  

Cheers

I had a similar issue with an older LCX unit.
The transducer signal would get lost (not when reversing, just randomly) and would then return anywhere from 1 minute to multiple hours later.
I was about to replace the transducer when the GPS signal from the LGC2000 also failed.
I made the assumption that the head unit was faulty and replaced it with a new HDS.
As it turns out both the transducer and GPS failed within about 3 months of each other, and the head until was "probably" OK (I didn't reinstall it just replaced the transducer).
I would suspect it is the transducer.
IF you can borrow another one would be worth a test I reckon.
The idea of swapping head units is a good idea.

 Mate looks like it's fairly common and an issue with the HDS series. I have an HDS 7 Gen 2 Touch which will all of a sudden lose bottom. It has happened mainly whilst at rest with motor shut down! After some time you look at the screen and boom she's back again?? It's very dissappointing as I upgraded from an old black and white unit which never lost depth just didn't show any detail to begin with!

However when it works I have been very happy with the unit, I also have the structure scan transducer which becomes confused due to the head unto not knowing which depth you're in. After some digging on the web please see below, when I get home will be trying the software upgrade, failing that will be on the blower to Navico.

http://www.thehulltruth.com/marine-electronics-forum/477561-lowrance-hds-touch-transducers-cutting-off-after-running.html

Let us know how you go,

Brydon

I am guessing your depth is on auto.

Try running your sounder on manual depth settings instead. If you prefer to run in auto maybe consider turning on the noise rejection and surface clarity. Fine tune these to find your prefferred setting until you find a happy medium.. If the sounder does jump up shallow while on auto and not re-find the bottom, you should be able to hit the range button set on manual and punch in a depth deeper than what you think is the actual depth, this should allow the sounder to find bottom and track it properly.

I hope that this sorts out you issues.

 I have the same problem with my HDS5........

Mine only spazzes out when travelling at speed in sloppy conditions. I thought it was due to the tranducer not keeping underwater? I have a 5m boat and its not that hard when travelling at speed for the arse end to rise out of the water and expose the tranducer.

I only turn it on now when at my spots or when travelling around slow looking for ground and its been fine............

 I had the same issue, need to select the right transducer. Makes a big difference 

OK, so the cleaned up wiring didn't solve the problem unfortunately.

Sulo, I tried the manual depth setting but that didn't help either.  Ian, mine has been fine in sloppy conditions and the problem just started up randomly so it's not an issue with the transducer coming out of the water.  Spitfire, the correct transducer is selected, and as above, the problem just started randomly with no settings or physical setup of the unit changing.  Thanks for the suggestions though!

I have now bought a P66 which is ready to be tested, so as soon as i get a chance, i'll update this thread with the results.  Fingers crossed!

So, good news -  it seems as though replacing the transducer has solved the problem!  Only taken the boat out once, but the sounder has not malfunctioned like it did previously.  It drops out with the initial turbulence (as to be expected), but now comes back straight away reading the correct depth.  Hopefully others may find this solution helpful if they have similar issues.

The only annoying thing now is that the P66 transducer cable is ~21ft long compared to the old 25ft Lowrance transducer cable, meaning it doesn't reach the head unit all tucked away neatly under the gunnels to the console.  I spoke to the supplier and they said that Lowrance request this length cable from Airmar.... but they do happen to sell a 3m extension cable.  Furuno and others all request a 25ft cable.  What cheeky f*ers Lowrance are.

Hey mate,

Just started having the same issue with my 5yr old HDS 8, losing depth indication after reversing and only starts reading depth again after prolonged power off. It looks like it's been a couple of years since you replaced the transducer, I was just wondering if the new transducer has held up long term or if the issue has reared up again at all? New P66 seems like path of least resistance if that works.

Cheers