Install back on a roots steel watch

I would take it to a jewelry shop or watch store.

If watch expensive, take it to Shop to get it changed , if watch waterproof, it needs to be changed at a shop, as when battery changed , shop checks that the watch is still 100% waterproof.

Razor blade to pop open the back. Remove the battery. Replace. Snap the back into place. This is easy if you arent worried about a watch that isn't worth much and didn't cost much. Don't get suckered into these services and click bait.

oPEN THE WATCH CASE BACK AND PUT THE NEW BATTERY IN.

All of the press on backs will have some degree of gap (should be able to fit a razor blade in) but .5mm sounds like far too much. Most probably the gasket is out of place or you need a new one. The gaskets in Tissot are notorius for displacing and mishaping upon a battery change. To get these special red Swiss gaskets you will need to go to a jeweler. I would call around to see who has Tissot style gaskets in stock because sending the watch out for repair will cost you at least $50 and this is an unnecessary cost.

Hate to say it but Wal-mart has the tools; seems like they'll do it for free if you buy the battery

Go to any walmart jewelry department and they will change the battery for you, and show u how to take the back off.

Take it to your local jewelry store, they will sell you a battery and install it for you. Watch how they do it for the next time.

Hi, I just encountered the same problem today as I was changing the battery and I found the solution. First make sure when you are changing the battery that the watch stem is pulled out; then after the battery has been replaced, and before you put the gasket and back on you will need to "reset" or "hotwire" the battery ....you are going to likely need a magnifying glass to find a tiny ac symbol on the back of the watch (without the back cover replaced)...just next to the ac symbol is a tiny hole. Take a piece of wire, or in my case I used an unfolded paper clip, and put one end of the wire in the hole and the other end on the back of the battery (the +/positive side should be facing up). Leave the wire in contact with the ac/battery for 5 seconds, then remove. Next replace the rubber gasket, then the back and the screws. Lastly, push in the watch stem. Your watch should now work. I found out through considerable research that almost all digital watches will need that "hotwiring" step performed after the battery is replaced.

dcraigpa

There is a tool that you need that adjusts to the three holes or openings in the back of your watch and it just screws off. If you don't have access to the tool, simply take two push pins and CAREFULLY insert them into the openings and unscrew the back cover. Remember that it unscrews counter-clockwise.This will give you access to the battery simply take it out and go to the store to buy a replacement repeat the process to install the cover back on.