Problems with Raymarine DSM300

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Luis Sa
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Problems with Raymarine DSM300

Post by Luis Sa » Tue Sep 26, 2017 2:03 am


I installed a DSM300 sounder module (and a P319 transducer) in the beginning of 2011. I connected the DSM to the C90W chartplotter using a NetGear 4-hub switch. These 2 items are installed in the space accessible from the back of the port side aft cabin. I will place here a photo next time I will go the boat. The P319I could get transducer was mounted near the DST8000V triducer.


I could get a power cable near the place where the DSM and the NetGear switch are mounted. This power cable comes from the VDO electrical panel and is controlled by the panel switch labelled as "Auxiliary". As far as I could understand this "Auxiliary" switch only connects/disconnects the DSM and the NetGear switch. So when I need the Radar or the Fish Finder I need to go to the main VDO panel and switch ON the "Auxiliary" switch. I found some erratic behavior on the DSM. It is good as it shows depths almost up to 1000 meters but sometimes it shows the error "DSM connection lost" which triggers an irritant alarm sound. In order to stop the alarm sound we need to press OK on the chartplotter. As I do not fish anymore, I get used to have the "Auxiliary" switch. Even when I needed the radar I used to go to the back of the aft port cabin, remove the door and disconnect the RJ45 plug (coming from the DSM) from the hub-switch. Doing so, I could use the radar without the irritating alarms when the DSM loses connection.

However, I started to have problems with the DST800 triducer. Water temperature and Speed are always fine but Depth fails from time to time. I noticed this for the first time in 2016, in the Golf of Thessaloniki, when depth is from 20 to 30 meters. It worked OK when depth was greater than 30 and also when it was less than 20 meters. I though that it could be something related to the characteristics of the sea bottom. But in 2017 it start to fail even at very low depths of 3 or 4 meters when I was in the Zea Marina in Athens. You can see here a post that I made in a forum to get help.

So, I returned to the DSM which was quiet for some years. And got the same behavior as before. And reading on the net I discovered that Raymarine replaced free of charge (in 2013 :cry: ) all DSMs made in Mexico by new ones made in Hungary. Another thing that I learned by reading the web was that the problem was related to the power supply. And I could confirm that. When I was running the engine (alternator working) the "lost connections" were very rare. And if I disconnected the freezer, no more "lost connections". And if the freezer was OFF and I switch OFF the engine or put it in slow rotation (alternator not charging the batteries) the "lost connections" reappear. When the alternator is charging the batteries the voltage measured at the batteries is about 14 V. The indicator on the VDO panel on the port side (the batteries are on the startboard) shows about 13V. And if the freezer starts (increasing the current by some 6A or 7A) the voltage at the batteries lowers a bit but at the VDO panel, the decrease is about 0,7V! This is too much as the cables from the batteries to the panel are very thick. So I need to check any loss of voltage in the contacts from the batteries, switches, up to the panel.

Nevertheless I ordered from AliExpress a step up/down 13,8V 10A switching regulator. The current peaks by the DSM can only reach 8A and so this regulator is fine. I will install it, next December, near the hub-switch and the DSM. I will post here the result. Meanwhile here is a picture of the referred to regulator. And I need to resolve what I will do with the 319 transducer!


Regards, Luis

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