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Macintosh SE motherboard not working, recap needed or else?

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  • 68kMLA Supporter

HI all,


I'm in process of repairing a Mac SE that does boot, it does not play chimes, the CRT quickly flashes a pattern of with squares and then it rests in peace blank and silent.

I did the following:

  • I added a new battery
  • I checked the diodes, all just fine
  • All the caps looks tidy with no sign or leakage.
  • I put the motherboard in the chassis of a working SE, same outcome
  • I put other know to work RAM, same outcome
  • I replaced the ROM with another set from a known working SE, same outcome
  • for a sort of regression test, I put back the original mother board in the chassis and all worked fine


Now: the MB was washed thoughtfully as I usually do with success

The surface looks perfect, no sign of corrosion, battery holder has no rush or sign of leakages,


The caps looks fine, but before replacing them I want to know the opinions of you guys, the video of the boot is attached hereby (the background noises have  nothing to do with the Mac)


many thanks




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  • 3 weeks later...
  • 68kMLA Supporter

Larry Pina's book does not help. For all the symptoms when the SE is silent with a black screen he is mentioning to check against for the Analog Board, but in my case it can not be, so even if the board looks tidy and neat I will go for the replacement of the capacitors.

May the force be with me



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Good troubleshooting. I'd wager that a recap does the trick. Not all caps fail spectacularly – sometimes they just sort of "boil off" without any noticeable change at all. Then there are the caps that do a perfect job of hiding just how much mess they've made beneath themselves... That was the case with my Classic.


Be sure to buy in bulk when ordering caps if you have a lot of Macs that could use recapping! I wish someone had given me a heads up as to just how many 47uF 16V caps there are in Macs of various vintages. 


Have you recapped any of the other Macs in your collection? Nice PowerBook selection by the way!

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