Tiiiincho
Level 1 (0 points)

Q: Fixing a Macintosh 512k! Broken mesh

I bought this Macintosh 512k which won't turn on for 30 bucks.
The guy who sold it to me said "the last time it worked, I heard an explosion and there was a lot of smoke".

 

I opened it and the only thing I saw that was wrong was this:

1544378_428768523924242_240213540_n.jpg

There are no broken capacitors and everything seems to be okay.

 

Now, the question is: can I fix that? Maybe bridging with a wire or something.

Posted on Mar 29, 2014 4:25 PM

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Tiiiincho

Q: Fixing a Macintosh 512k! Broken mesh

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  • by Jan Hedlund,Helpful

    Jan Hedlund Jan Hedlund Mar 29, 2014 6:01 PM in response to Tiiiincho
    Level 6 (9,901 points)
    Mar 29, 2014 6:01 PM in response to Tiiiincho

    >Now, the question is: can I fix that? Maybe bridging with a wire or something.

     

    Generally speaking (since I do not know any details about this case), wires can sometimes be used to repair broken traces. However, it is of course important to first determine the cause of the damage. There must have been a short-circuit or overload somewhere, so one would have to check/measure all relevant components.

     

    Please note that working inside a compact Mac is very dangerous because of high-voltage circuits. Charges can remain for a long time even after the computer has been switched off and disconnected from the mains. Work like this must only be carried out by someone with the necessary expertise.

     

    Classic Mac Repair Notes by Thomas H. Lee (try a web search) could possibly be of interest.

     

    Jan

  • by Appaloosa mac man,Helpful

    Appaloosa mac man Appaloosa mac man Mar 30, 2014 10:01 AM in response to Tiiiincho
    Level 5 (4,330 points)
    Mar 30, 2014 10:01 AM in response to Tiiiincho

    Tiiiincho

     

    I would follow Jan's advice totally.  Safety and tracing causation are important.  Having said that, my mind moved on to what might have caused the problem in the first place.  Let me give an example.

     

    Take apart a non-functioning vcr and you might find crayons that a child has poked into the device.  Remove the crayons and the vcr might work just fine again.  What if a foreign object got into the compter?

     

    We have taken computers apart, only to find a loose screw under the motherboard.  The screw was shorting something out, causing a malfuntion.  Remove the screw and the computer goes back to normal.

     

    Without knowing the cause of the problem, we are free to speculate!  The image makes me wonder if dust, a paperclip, staple or other small metal object may have bridged the two 'wires' and caused a short.  The heat from the short may have caused the damage at both ends.  If, big emphasis on IF, such was the cause of the damage, then simply restoring continuity would be just fine.  At a minimum, we can conclude that it is heat related damage.

     

    The physician's creed of 'do no harm' is what Jan is warning to avoid.  My two cents would be "what do you have to lose?"

     

    Radio Shack sells (sold?) copper paint for the task.  Do a web search for 'conductive paint circuit board' for other sources. Obviously, the contacts will have to be cleaned, soldered and resealed to give a good connection and protection but what you use is up to you.  It is well out of warranty!

     

    Some notes of possible interest:

     

    http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-et c/

     

    http://www.talkbass.com/forum/f38/diy-conductive-paint-cavity-shielding-589012/

  • by Tiiiincho,

    Tiiiincho Tiiiincho Mar 30, 2014 11:38 AM in response to Appaloosa mac man
    Level 1 (0 points)
    Mar 30, 2014 11:38 AM in response to Appaloosa mac man

    I am pretty sure of what caused the problem.

    I'm from Argentina, and so is the man who sold it to me. I don't know how is it up there, but here, when you plug in something to the wall, it recieves 220v. This Macintosh uses 110v. I think that man just connected a 110v device to a 220v plug. And... boom.

    There's nothing else wrong inside. It isn't even dirty! (Well, not really dirty).

     

    I will try to fix the trace with a wire, get a 220v to 110v transformer and try.

     

    I'll keep you informed!

  • by Appaloosa mac man,

    Appaloosa mac man Appaloosa mac man Mar 31, 2014 1:04 PM in response to Tiiiincho
    Level 5 (4,330 points)
    Mar 31, 2014 1:04 PM in response to Tiiiincho

    Tiiiincho

     

    Thanx for the update.  My son was gearing up for time in Brazil.  We looked at transformers and then looked at his Apple devices.  His devices are auto-switching from 220v to 110 v as needed.  His AA battery charger is also auto-switching.  Solution:  take lots of rechargeable AA batteries for everything else.