PowerBook Duo 280c no power Help!!!

Discussion in 'Apple Collectors' started by iBook_Clamshell, Jan 6, 2017.

  1. iBook_Clamshell macrumors member

    Aug 27, 2013
    Hello guys,
    I bought a PowerBook 280c a while back. The guy I bought it from said it worked when he stored it 2 years ago, but it longer booted up. I got it for a pretty good deal along with a NIB power supply and a battery of unknown condition.
    I have not succeded in coaxing life out of this guy. I have tried it with a known good power supply, with and without batteries, I even removed the backup battery and did the PMU reset. No change. When I plug the AC adapter in, I hear the ticking of the working DC-DC circuit. By having the lid closed and pushing the button on the back, I noticed that sometimes the sleep light will blink 10 times in a row, kind of like a code.
    The most interesting thing was when I put it in my dock. The power supply of the dock made a high-pitched whining sound and nothing would respond; I had to manually eject the duo.
    We have removed the capacitors from the board, since they probably need replacing anyway. There was a small puddle underneath each cap! In removing the caps, some of the pads came with them. How can that be fixed?
    Any ideas on why the laptop wouldn't run?

    I have a 2300c that works fine with the dock and all the accessories. If anybody has a working 280c or even a good motherboard, I would be interested in a partial or full trade.
  2. MacTech68 macrumors 68020


    Mar 16, 2008
    Australia, Perth
    Sounds like something shorting out a power rail in the 280c or at least excessive load that causes the powersupply to shutdown - the power supply then has no option but to power-up again - rinse, repeat. Hence the ticking, chirping, thumping and blinking light. In reality, this could be any cause.

    But it could be caused by leaked electrolyte causing a switching regulator to "go nuts", drawing excessive current.

    As for the lifted tracks, the pros use special kits with replacement strips and pads of all kinds of sizes - however, SOMETIMES you can scratch the remaining track back to copper for a short distance to allow you to bridge to a replacement cap, or using a piece of wire if the gap is too wide to bridge. Personally, I use prototyping wire where longer runs are needed, but you can get away with a single copper thread of wire from a multi-stranded cable. It's tedious work, and you need to clean any track or component legs that appear black or corroded.

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