원문 게시자: oldnwstf ,
Although you do not see any capacitor leakage, there is almost certainly some under the capacitors. These machines are now all 25+ years old and all require capacitor replacement for proper or reliable operation. Capacitors have small rubber seals underneath that perish and leak electrolyte solution. I own a small collection of Classic Macs and PowerBooks and all had bad capacitors. Some even from as late as 1996. Even if the machine would work, it would have a weak sound or it would crash from time to time with bad capacitors. PRAM batteries are not necessary in PowerBook 100 model! I am running my without them and it works perfectly, although it wont keep date and time. Just replace all SMD electrolytic capacitors with new ones (preferably with MLCC or tantalum) and you will be fine. Radial ones (leads soldered on the opposite of the board) are usually fine. PowerBook 100 also has some capacitors on the LCD panel which must be also replaced. These are 3.3uF at 35V. Use MLCC ones for this application. When these go bad, you will have blank or black screen, or/and unstable contrast.