I have an Autohelm ST 50 Plus depth gauge and knot meter on my 91 Hunter 27. a month ago i went out for a sail and i notice the depth gauge did not come on when I flipped the breaker switch. The knot meter did come on and worked properly. The next time out i was going to trouble shoot the problem thinking it might be a blown fuse. when i hit the breaker both the depth gauge and knot meter came on and work perfectly every weekend untill last Sunday, when the depth gauge did not come on all day while the knot meter worked fine. throughout the day i hit the breaker off and on and it never came back up..... any suggestions on what could be wrong and how to fix it? i am somewhat electronically challenged, about all i can do is replace a fuse... Alan
Depth gauge not working
- Thread starter RAC
- Start date
- Status
These instruments are connected in series dor both power and data. From your observations, I would suspect a bad or loose connection between instruments. Try re-seating the connectors. Since your knot meter always works and the power from your panel to the two instruments is common, I would not suspect a bad connection at the panel or a bad fuse somewhere.
When you state that the depth does not work, I am assuming that there is no display at all, hence no power. If you have a display but no data, then check the cables to your hull transducer for bad connections or damage.
When you state that the depth does not work, I am assuming that there is no display at all, hence no power. If you have a display but no data, then check the cables to your hull transducer for bad connections or damage.
Designed to Leak?
Quite by chance I wrote the following for the UK Legend Owners a month or so ago.
Designed to Leak? …. Autohelm/Raymarine ST50 Instruments
A couple of years ago my 1996 Autohelm/Raymarine ST50 Echo Sounder stopped working. Being short of time I took the instrument head to Raymarine's HQ and paid for them to test it. I collected it a week later with 'Nothing Found' as the diagnosis. I reasoned that it must be the transducer and duly bought a replacement, hauled the boat and fitted the replacement transducer. All worked okay. Problem solved – great.
Last fall the sounder problems returned. This time I decided to investigate for myself.
So I took the 1996 instrument off the console, brought it home and opened it up. There was a 'tide mark' about ½" up from the bottom of the printed circuit and two components had been completely corroded away. Clearly it had been leaking, hopefully only rainwater! I had no idea how long this had been going on but it seemed likely that this was the cause of the previous problems also - but removing the head from the boat and having it indoors for two weeks had given it a chance to dry out.
The cause of the leak was obvious. The instrument case has a smart red molded rubber gasket to seal the case front to back and the edge shows, making a feature which must have helped their sales no end.
But the four screws which hold the back to the front are positioned, one in each corner, and inside this gasket's protective ring. So, water which trickles down the gap between instrument and bulkhead can very easily find its way into the recesses where the screw heads are. From there it just percolates under the screw heads and into the instrument. There were no little rubber seals on these four self tapping screws either.
This is my second instrument to suffer this defect because, some time earlier whilst sailing in very hard weather, the water level inside my log came half way up the LCD display!
We sorted that by opening the case and shaking the water out and then left it in the sun all day.
Anyone with these ST50 instruments is strongly advised to simply put small patch of self adhesive tape over each screw recess on the back of the case and then to apply a single turn of tape right round the join between front and back halves of the case. Even if you decide not to get to the backs of the cases for the four patches over the screw heads, having the round turn of tape over the case joint will protect against frost opening the join and letting the water in.
Then I drilled a 1/16" hole upwards on the bottom outer corner of the case. By drilling midway between front and back and about 3/8" in from the outer edge the drill just pierces the case and abuts onto a solid screw support inside. This means it does not go near the printed circuit nor does any swarf get inside in a place where it could cause trouble. The last photo shows these holes.
However, do not seal or block the small hole on the underside of the 2" diameter round projection at the back of the case as this is necessary to help keep it from steaming up in conditions oh high humidity.
I used a weatherproof PVC tape as used by electricians, but any ordinary tape including self amalgamating would suffice.
Quite by chance I wrote the following for the UK Legend Owners a month or so ago.
Designed to Leak? …. Autohelm/Raymarine ST50 Instruments
A couple of years ago my 1996 Autohelm/Raymarine ST50 Echo Sounder stopped working. Being short of time I took the instrument head to Raymarine's HQ and paid for them to test it. I collected it a week later with 'Nothing Found' as the diagnosis. I reasoned that it must be the transducer and duly bought a replacement, hauled the boat and fitted the replacement transducer. All worked okay. Problem solved – great.
Last fall the sounder problems returned. This time I decided to investigate for myself.
So I took the 1996 instrument off the console, brought it home and opened it up. There was a 'tide mark' about ½" up from the bottom of the printed circuit and two components had been completely corroded away. Clearly it had been leaking, hopefully only rainwater! I had no idea how long this had been going on but it seemed likely that this was the cause of the previous problems also - but removing the head from the boat and having it indoors for two weeks had given it a chance to dry out.
The cause of the leak was obvious. The instrument case has a smart red molded rubber gasket to seal the case front to back and the edge shows, making a feature which must have helped their sales no end.
But the four screws which hold the back to the front are positioned, one in each corner, and inside this gasket's protective ring. So, water which trickles down the gap between instrument and bulkhead can very easily find its way into the recesses where the screw heads are. From there it just percolates under the screw heads and into the instrument. There were no little rubber seals on these four self tapping screws either.
This is my second instrument to suffer this defect because, some time earlier whilst sailing in very hard weather, the water level inside my log came half way up the LCD display!
We sorted that by opening the case and shaking the water out and then left it in the sun all day.
Anyone with these ST50 instruments is strongly advised to simply put small patch of self adhesive tape over each screw recess on the back of the case and then to apply a single turn of tape right round the join between front and back halves of the case. Even if you decide not to get to the backs of the cases for the four patches over the screw heads, having the round turn of tape over the case joint will protect against frost opening the join and letting the water in.
Then I drilled a 1/16" hole upwards on the bottom outer corner of the case. By drilling midway between front and back and about 3/8" in from the outer edge the drill just pierces the case and abuts onto a solid screw support inside. This means it does not go near the printed circuit nor does any swarf get inside in a place where it could cause trouble. The last photo shows these holes.
However, do not seal or block the small hole on the underside of the 2" diameter round projection at the back of the case as this is necessary to help keep it from steaming up in conditions oh high humidity.
I used a weatherproof PVC tape as used by electricians, but any ordinary tape including self amalgamating would suffice.
Attachments
- Status