Horizon MD-50 Speed/Depth Problems

[chall03]

I have a Horizon MD-50 Display that has been doing fine, however of late it is producing widely inaccurate results. As my boat sits happily in its slip at the moment the display is reading a depth of 35 Metres, the real depth is about 3 metres. The Speed is reading 5.4knots.......

Ok what have I done so far??

-I checked the depth thru-hull when I slipped the boat, and seems is clean as, except for a new coat of antifoul of course, I know some people don't paint over the Transducers, but I have been told that alot do and this shouldn't be a problem?

-There is only a small adjustment/caliberation possible on the unit, + or - a metre or two to set Keel offset etc, but certainly not enough to sort out an error of 30+ metres....ditto for speed a small adjustment only....

-I have disconnected the depth thru-hull transducer and turned it off and on again etc, and with even with thru-hull disconnected it is still convinced that there is 35m of water.

I'm at the point where I don't know what to try next....any ideas??

Or should I assume the display has had it and replace?
If I do replace the MD50 with another unit, would I also have to replace my Transducer or could it be made to work with a new unit? Ideally I would like to not replace the Transducer

Thanks in advance for any suggestions or advice.

[GordMay]

Originally Posted by chall03

... except for a new coat of antifoul of course, I know some people don't paint over the Transducers, but I have been told that alot do and this shouldn't be a problem ...

What do the experts who advised that you could paint the transducer say? I would not have so advised.

Could the instrument be in “simulation” mode? (Push “bell” button then turn power on)

See the Knot-Log (speed) “Tap-Test” procedure at:
http://www.cruisersforum.com/forums/...ent-15440.html

Check out Airmar for a suitable replacement transducer, if needs be, at:
Airmar Ultrasonic Air Products

[chall03]

Thanks for the advice Gord.
I looks like you were very much on the money I contacted Standard Horizon, and their tech support couldn't of been more helpful, they too suggested that it is porbably in simulation mode and gave me instructions on how to get it going again.....As of yet haven't been able to get to the boat to test, but it is looking good.