Many early Macintosh computers, such as the Mac SE, have soldered PRAM batteries. While designed to last for many years, these batteries are now decades old and prone to leakage.
Thankfully, for many vintage Mac models, a working PRAM battery is not strictly required for the computer to start. The machine will boot, but it will lose settings—a small price to pay for keeping a piece of computing history alive. MACINTOSH PRAM BATTERY
If your vintage Mac is suddenly living in 1956 (or 1904, 1984, etc.) every time you turn it on, the PRAM battery is likely dead. 2. The Danger Component (Soldered vs. Holder) Many early Macintosh computers, such as the Mac
Enthusiasts often carefully cut or desolder these old batteries to remove them before they destroy the logic board. 3. "Not User-Serviceable" (Technically) The machine will boot, but it will lose
Later Power Macintosh models often require a working PRAM battery to function properly.
Getting Started With Your Vintage Macintosh – Garrett Fuller