Casio AC reset not working: what to try next
Casio AC reset not working: what to try next
You shorted the AC contact, the screen is still blank, and the internet's one-line advice has run out. Work through this list in order — it's sorted from most common cause to least.
1. The new battery is the problem more often than the watch. Coin cells sit in shop drawers for years; a "new" battery can arrive half-dead. Test it in another device or measure it (a healthy CR cell reads ~3.0-3.2V), or just try a second battery from a different pack. This single step resolves a surprising share of "dead after battery change" cases.
2. Check the battery is the right way up and the right thickness. The + side faces up in nearly all Casio bays. And a CR2016 in a CR2025 bay may simply not touch the contacts — see the substitution guide.
3. Redo the AC short properly. Bridge the AC contact and the battery's TOP (+) surface with metal tweezers, and hold for a full five seconds this time. A half-second tap sometimes isn't enough. On some modules you must do this while the battery strap/clip is properly seated, not floating.
4. Look at the contact springs. The small springy contact under or beside the battery must press firmly against the cell. If a previous battery change bent it flat, the module has power on paper but not in practice. Re-tension it gently upward with a toothpick.
5. Check for residue. A faint white crust on the contacts from an old leak blocks current invisibly — clean with isopropyl alcohol and look again (leak guide).
6. Your module may reset differently. A few modules ignore the AC pad and want the battery out for thirty seconds, or all buttons held together with the battery in. The module number on the case back plus "reset" finds the exact ritual — our module guide shows where the number lives.
Still nothing after all six? With a verified-good battery, clean contacts and a proper reset, the module itself is the likely casualty — usually from an old leak. For common modules, a donor watch costs less than lunch and swaps in with the same four screws.
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