Changing McMurdo E3 EPIRB Battery

Recently, I have to change an expired McMurdo E3 EPIRB battery. I never changed an EPIRB battery before but after understanding its internal structure, I am confident enough to try for the first time.

The replacement kit comes with a battery unit, a gasket, a silica gel package, new battery expiry date sticker and 8 pieces of new screws.

This is how the new gasket looks like. It is used to replace the existing gasket on the top/antenna housing

The screws comes with o-ring to ensure watertight integrity to the EPIRB unit

First of all, remove all the holding down screws around the housing usng a flat face screwdriver. Total of 6 screws if not mistaken.

There are 2 screws hidden behind the lanyard. Pull the lanyard holder to reveal the screws ports (2)

After removing all the screws, gently pull up the top/antenna housing to disengage it from the lower part of the unit. The printed circuit board can be seen after the top housing been removed.
The printed circuit board is been secured with 3 screws

Use the Philips screwdriver to remove the centre screw. Extra precaution not to lose the washer below the screw

Then remove the spacers by either removing screws from the bottom of the spacers or loosen the spacers with finger. There are washers below the spacers and should be careful so not to lose the washers

Slightly lift up the circuit board gently. The battery unit can be seen at the bottom of the printed circuit board.

Try to locate this 2 connections attached to the printed circuit board. One of the connection is to the battery unit and the other one is to the unit test button. Gently disengage the connectors from the printed circuit board.

Note there is an old silica gel package (white package) at the bottom of the printed circuit board.

Remove the previous silica gel and replace it with the new one which comes with the replacement kit. Use the double sided adhesive tape to ensure the new silica gel glued to the area. The purpose of the silica gel is to keep the internal area dry from moisture

With the printed circuit board removed, the battery unit is visible underneath it

Use a narrow head plier to loosen the bolt that is securing the battery unit. There is a washer below the nut and be careful not to lose it.

After the nut is removed, the battery will slide out easily. There is a tiny shaft in the middle that secure the battery unit.

Change the gasket for the top/antenna housing

Reassembled it in the reverse order. Once it is reassembled, push and hold the test button for 10 seconds to ensure the EPIRB unit is in working condition and able to transmit.

Lastly, put on the new battery expiry date sticket on the EPIRB unit. The battery has a lifespan of 5 years.

Also the EPIRB casing should be updated with the new battery expiry date sticker.