How to Replace Battery on Timex Ironman Triathlon Watch

How to Replace Timex Ironman Triathlon Batteries-Main
How to Replace Timex Ironman Triathlon Batteries

My trusty Ironman Triathlon began getting dim on me about a week ago and then it was acting strangely–finally it went blank on me.  Time for another repair.

How to Replace Battery on Timex Ironman Triathlon Watch


Tools Needed

Parts Needed

Step 1: Unscrew the four phillips screws on the back of the watch.

I have a set of precision screwdrivers like the set I have linked in the “Tools Needed” section and the smallest phillips screwdriver works fine.  The screws are small so make sure to set them aside where you are not going to loose them.

Unscrew the Four Back Screws
Unscrew the Four Back Screws
Four Back Screws Loosened
Timex Ironman Triathlon-Four Back Screws Loosened

Step 2: Remove the back.

There are springs the push on the back for the piezoelectric speaker so the back will want to come off.  I used a small flat screw driver and gently nudged up on the edge and the back popped up.

Gently Prying off the Back with a Flat Screwdriver
Gently Prying off the Back

Step 3: Remove the battery cover screw and lift off the battery cover.

There is one screw that holds a metal shield down over the battery.  Remove that screw:

Battery Cover Screw Location
How to Replace Timex Ironman Triathlon Batteries-Battery Cover Screw

The battery cover tucks in on the top edge so lift from the bottom side (the end where you removed the screw).  The battery cover will stick to the battery because of that red sticker and when you lift up the battery cover the battery will lift out as well.  You do not want to remove the watch internals or you will make the job more difficult (like I did).  Peal the battery cover off the battery and you will have something that looks like this (pardon the slightly out-of-focus image):

Old Battery and Battery Cover
How to Replace Timex Ironman Triathlon Batteries-Old Battery and Battery Cover

Step 4: Insert a new battery into the watch.

Lay the battery with the button end down like this with the positive (+) side up:

New Battery Inserted
New Battery Inserted

Step 5: Reinstall the battery cover.

Start by hooking the top of the battery cover in its slot and then lay the battery cover down, centering it over the battery and lining up the hole where the screw will be inserted:

Inserting Battery Door into Slot
Inserting Battery Door tab into Slot

Then reinstall the battery door screw:

Reinstalling the battery door screw
Reinstalling the battery door screw

Step 6: Reinstall the waterproofing gasket

Chances are, the rubber gasket that keeps water out of the watch will jump out of its channel when you take the back off.  I completely removed the gasket and cleaned any debris off of it:

How to Replace Timex Ironman Triathlon Batteries-Back Gasket
Waterproofing gasket removed

Insert the gasket back into its channel as seen below:

Back Gasket in Channel
Back Gasket Reinstalled in Channel

Step 7: Reinstall the back

With the top of the watch at the top, reinstall the back so the lettering imprinted in the back of the watch is right-side up:

Reinstalling the Back
Reinstalling the Back

Reinstall the four screws.  I held the back on tightly as I screwed them in:

Reinstalling the 4 Back Screws
Squeezing the Back on Tightly While Reinstalling the 4 Back Screws

Step 8: Set the Time

The on-screen instructions are pretty good compared to digital watches of yesteryear.  Use the START/SPLIT button to increase the number, use the STOP/RESET button to decrease the number, use the MODE button to advance to the next setting and the SET/RECALL button for Done.

Setting the Time
Setting the Time

The Date, Day, and time are set:

Time Set
Time Set


If buttons don’t work

The first time I reassembled the watch the STOP/RESET button didn’t work.  I had to take it apart and in doing so I realized that the entire watch insides were not quite lined up with the buttons.  Make sure the metal tab at the right and the left are not tucked under and make sure the buttons line up with the arched part of the spring arms as indicated in the image below:

Lining Up the Insides
Lining Up the Insides

There are two buttons on each side that needs to line up with the curved metal spring piece and one metal tab that should be on top.

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