My 280c that hadn't been used for years wouldn't boot and came up with the 4 death chimes.
The capacitors had leaked (possibly when I turned it on, because the board doesn't seem to have any corrosion on it), so I cleaned both sides with alcohol and replaced the 7 electrolytic capacitors on the logic board, but it still comes up with the 4 death chimes.
Tried booting without the memory board/battery/SCSI disk and still death chimes.
The power supply seems to be working (although there is a slight fishy smell from it). It gives out 25 volts when no load and goes down to about 23.8 when the powerbook is booting. There doesn't seem to be any capacitor leakage in the power supply when I opened it up and can't see any obvious bad components (or work out where the fishy smell is coming from).
Took a quick look at the display PCB and there doesn't seem to be any capacitor leakage there (and I can sometimes get a brief 'random lines' on the display when pressing the power button to turn it off, so I think the display is working).
The leakage from the capacitors was a slight, thin clear film and had only spread just to the immediate area around the capacitors. It may have gone under the 2 transformers, but can't get there to clean it up. I tested the leakage from the capacitors and it doesn't seem to be conductive.
Any suggestions? I can't see any corrosion or obvious broken components on the logic board. The only thing is just a very slight grey fuzz on the ends of the SMD (capacitor?) component between the 2 (serial?) chips on the underside of the board on the opposite side to the power capacitors.
The capacitors had leaked (possibly when I turned it on, because the board doesn't seem to have any corrosion on it), so I cleaned both sides with alcohol and replaced the 7 electrolytic capacitors on the logic board, but it still comes up with the 4 death chimes.
Tried booting without the memory board/battery/SCSI disk and still death chimes.
The power supply seems to be working (although there is a slight fishy smell from it). It gives out 25 volts when no load and goes down to about 23.8 when the powerbook is booting. There doesn't seem to be any capacitor leakage in the power supply when I opened it up and can't see any obvious bad components (or work out where the fishy smell is coming from).
Took a quick look at the display PCB and there doesn't seem to be any capacitor leakage there (and I can sometimes get a brief 'random lines' on the display when pressing the power button to turn it off, so I think the display is working).
The leakage from the capacitors was a slight, thin clear film and had only spread just to the immediate area around the capacitors. It may have gone under the 2 transformers, but can't get there to clean it up. I tested the leakage from the capacitors and it doesn't seem to be conductive.
Any suggestions? I can't see any corrosion or obvious broken components on the logic board. The only thing is just a very slight grey fuzz on the ends of the SMD (capacitor?) component between the 2 (serial?) chips on the underside of the board on the opposite side to the power capacitors.
