Replacing Battery in RayStar 125 GPS Unit

[dkinzer]

The last few times that we took our boat out we got a message on our MFD indicating that the GPS fix was lost. This occurrec on several outings and always just after the nav instruments were powered up. I found a couple of videos on YouTube showing how to take the RayStar 125 apart and replace the CR2032 "coin" battery in it. Apparently, that battery allows the unit to retain satellite data across power cycles.

The RayStar 125 unit is flat-mounted on the starboard side deck aft so I'll need to break the seal between the unit and the deck once I locate the affixing screws on the underside of the deck. I'll probably wait for nicer weather to do this in case I run into an issue that turns it into a multi-day project. A photo of our installation is attached.

My questions are:
1) Has anyone here done this on a surface mounted unit?

2) What would be a good sealant to use when re-seating it to the deck? I don't know what was originally used (hoping it wasn't 5200) but I'm thinking either butyl tape (or Bed-It tape if it becomes available again), or Dow 795 or 4200 or even 4000.

 

[kappykaplan]

What would be a good sealant to use when re-seating it to the deck?

4200 or 795 get my vote in this application.

 

[dlochner]

or Bed-It tape if it becomes available again

Bed-It Bed-It Tape

Bed-It Bed-It Tape

shop.sailboatowners.com

Departments - BUTYL TAPE BED-IT 1/2" x 50' ROLL

Bed-It Butyl Tape, 1/16" thick, 1/2" wide x 50' roll. Gray. This tape is specifically formulated and extruded for the installation of deck fittings to the decks of boats. All aspects of the installation procedure and necessary formulation requirements have been brought together in a marine...

shop.hamiltonmarine.com

 

[Kent C]

I replaced battery in my rs125 a couple years ago on 08 hunter 33 which is mounted on starboard deck
1. you need access to bottom of it to undo the thumbscrew nuts below the unit.
2. take an olfa knife with blade extended and carefully cut between unit and deck. the wire comes up the middle so stop cutting about 1" from center. should be able to wiggle it up with the wire.
3 wire plugs in similar to a ethernet cable.
4. screws on bottom take unit apart and can get to ic board
5. battery was just a clip in so no soldering. get a good 2032 battery made recently.

I used sikaflex to seal back up and have had no leaks yet.

My rs235 was loosing fix last year. so I think is either at end of life, because of location is blocked or did gps satellites all get moved around for various reasons. I notice that it will find satellites but have little to no signal from them.
I also have a garmin 740s mounted on arch and it never looses fix.

On raymarine site is states rs125 may no longer function after 2023 as program only for so many weeks. currently looking for a reasonable priced replacemnet as to go with raymarine suggestion would be almost $700cdn with adapters etc

Kent

 

[Ted]

I changed the battery in my RS125 a few years ago. When you flush mount the unit to the deck, you don't use a sealant. It is supposed to be mounted with a gasket supplied by Raymarine. If the previous owner of your boat didn't remove the gasket, you should be able reuse the gasket when reinstalling the GPS. Just be careful when you remove it from your deck so you don't destroy it. Butyl tape around the deck holes would be a good alternative.

 

[RoyS]

You could purchase silicone sheets from Amazon and cut a gasket out of those. I have used that material for several on deck gaskets, including bimini mounts and engine shifter base.