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  1. #1
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    Post Apple Macintosh Classic - Risky Repair Job(not really)

    I think my macintosh classic is showing signs of capacitor leakage.
    It boots up fine when I first turn it on after been powered down for weeks/months but once I turn it off and then back on a few mins later I get the classic checker-board screen and no boot. Now, if I leave it powered up it will eventually boot(after 2-3 hours). This can be a ram/ram connector issue or more than likely a leaky cap or caps.

    Now I've opened her up and I thought it was fine as there was no obvious signs(very clean and in great condition actually).
    But after a closer inspection there might be some around a couple of the caps(kind of looks like a little bit of oil was rubbed around them).



    I cleaned the board with cotton wool buds and cleaning alcohol stuff and still the same problem.

    So I've decided to try out a bit of a more risky fix but one that has proven successful with issue like this in the past(on old macs anyway).
    I'm going to run the main board through the dishwasher
    It's not as crazy as it sounds as long as certain precautions are taken. I'm going to pop out any rom chips that are socketed(hence easy to take out) and if it had any removable ram on the board that would come out as well(it doesn't).

    So the plan is to put the board in the dishwasher now, run it through on a warm but not hot wash(eco wash on my dishwasher). I only put a very small amount of detergent in with it(less than half a tablet). Once the wash is done I'll dab dry it and then dry it again with cotton buds.
    Once that's done I'll put it on a non metallic oven plate and put it in the fan oven at a very low temp, like 30-40 degrees for 20-30 mins(while keeping an eye on it and the temp inside the oven.

    That's the plan, hope it works this time as it did the last couple I did 5 or 6 years ago.

    I'll post up some pics a little later.

    Edit:
    Lots of pics added:









    You can see some build up of some sort of dirt/dried fluid or something else on these pots(these are not caps).




    The main motherboard with RAM board removed.




    Main motherboard with RAM board(next to a dusty lamp)




    The 3.6V PRAM Battery.








    I cleaned up the stuff that was on these(still not sure what it was).








    If you get a bad cap leak on the mac classic you'll find lots of goop on the back of the case(none on this, in fact its in great shape just like the rest of the system).




    I'm always a bit hesitant about sticking electronics in a dishwasher, it feels unnatural even though I know its fixed these issues in the past.





    More pics to come as soon as the board is out of the dishwasher


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    Last edited by RetromanIE; 25-03-2015 at 05:42.
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  2. #2
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    Fresh out of the dishwasher






    And now into the oven:




    Check the temp is just right(it is):




    Right, going to leave it in the oven with the fan on for 30mins. I'll be checking it as it goes to make sure it doesn't get to hot.

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    Last edited by RetromanIE; 25-03-2015 at 05:44.
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  3. #3
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    Update:

    It hasn't fixed the issue but at least its ruled it out(and the board is nice and clean).

    The next possibility is the RAM or RAM board but I don't thing this is it. I think it might be the PRAM battery as there is an issue that some people have come across that if the battery is dead or on its way out it doesn't hold the settings(which is normal) but they also say that SoftPower circuit is not getting enough power from the battery to start the Mac and apparently the PRAM battery also handles the ADB control and the SoftPower circuit.

    So I've ordered a new battery on ebay(about 5 euro) and I'll replace it and see what happens.

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  4. #4
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    Well, I got the new pram battery for the mac classic and still the same problem
    Looks like I'll need to research more but it's probably just the caps need doing.


    The batteries(clicky clicky for biggie):



    Old battery on the left.


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  5. #5
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    After over a month of having this unplugged I decided to power it up tonight and see what happens.
    It booted fine and everything seems ok(for the moment).

    So, is this a cap issue or something else???

    At least I know the dishwasher didnt kill it

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