SRAM backup battery dead; saves not retained between sessions.
5 repair logs
NEC — PC Engine IFU-30
Capacitors, voltage regulator and the supercapacitor that keeps the save data alive on this NEC PC Engine IFU-30 interface unit. Validated with Street Fighter II and Bomberman '94.
Battery and cap replacements on Super Metroid and Zelda, with saves backed up and restored throughout. Initially used tabbed batteries as a stopgap, then swapped to coin cell holders once they arrived.
Fresh batteries in a couple of recently acquired Game Boy carts, saves backed up and restored using an Open Source Cartridge Reader.
F-RAM upgrade across a couple of N64 Controller Paks. No more worrying about batteries quietly erasing your saves.
SNK — Neo Geo CD
A cheap Neo Geo CD from 2021, recapped board by board: the AV and power board, the optical drive PCB, the mainboard and the original PSU. Later fitted with a NEO SD Loader to take the load off the drive, and an F-RAM save mod after it stopped holding saves even with a fresh battery.