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Thread: Mac II relife

  1. #11

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    Quote Originally Posted by Elvi View Post
    I've seen these numbers before but i can't really make heads or tales off them especially pin 13 and 15, doubt a atx or at psu has those.

    If i had some shematics then i probably could work it out some day but i've seen none on the net for either at or atx.
    I am guessing N/C means "No Connection", as it frequently does in pinouts. PFW is power-fail/power-on circuit, something which I am pretty sure doesn't work the same on ATX, and something that would be dangerous to "fake", its purpose in the Mac is to 1. respond to power key on ADB keyboard (less critical) and 2. be able to initiate SHUT DOWN on the Mac in case of thermal runaway or other damaging events. If you really want to fake it and power-up with an ATX supply (and very likely destroy the board) +5v should in theory be applied to PFW to bring the power online.

  2. #12

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    I really don't have anything to loose here as i have no spare parts to test with and it won't turn on at all, i guess this would be easier with an AT psu as if the PFW is the one that needs +5 and the rest of the pinns are allready on a AT psu so i'd just have to hit the on switch on the psu... hopefully, thoughts?

  3. #13

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    Quote Originally Posted by Elvi View Post
    I really don't have anything to loose here as i have no spare parts to test with and it won't turn on at all, i guess this would be easier with an AT psu as if the PFW is the one that needs +5 and the rest of the pinns are allready on a AT psu so i'd just have to hit the on switch on the psu... hopefully, thoughts?
    AT or ATX, either one should supply the voltages needed, but either one will leave the PFW not working as it should, try it at your own risk, but its likely you will toast that thing.

    Best bet if you want to see this thing live again would be to replace all the electrolytic capacitors, those are the likely culprits to why its not powering on now. I would say after you have replaced those, and put fresh PRAM batteries in it and it STILL wont power on.....then I would say you have nothing more to loose, those are NOT expensive things to try first, you are looking at about $10-15USD (with postage) in parts and an hour of time. Those shouldn't be TOO expensive of parts in Finland either, there has to be SOME kind of electronics store (local or mail-order) that sells those types of parts, even if its a touch more than they would cost here in the states, if nothing else you can order that stuff for next to nothing from china it you have the time to wait.

    In the end its your stuff, if you want to just "apply power" and see, its up to you, just saying I would be trying a few things before that step.

  4. #14

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    Shouldn't the capacitor tops be bulgy or leaking if they have failed? i can't see any of that.
    Also it doesn't tell me if the PSU itself is bad or not.

  5. #15
    Join Date
    Sep 2011
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    Nova Scotia, Canada
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    Quote Originally Posted by Elvi View Post
    I've seen these numbers before but i can't really make heads or tales off them especially pin 13 and 15, doubt a atx or at psu has those.

    If i had some schematics then i probably could work it out some day but i've seen none on the net for either at or atx.
    This is what your connector should look like:


    http://i1246.photobucket.com/albums/...tt-k/power.jpg


    1 Yellow (+12V)
    3 Red (+5V)
    12 Black (GND)
    14 Blue (-12V)

    Ground the green wire on the ATX power supply to turn it on.
    This powers the Mac directly, so you don't need pin 15.

  6. #16
    Join Date
    Sep 2011
    Location
    Nova Scotia, Canada
    Posts
    24

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    Quote Originally Posted by Elvi View Post
    Shouldn't the capacitor tops be bulgy or leaking if they have failed? i can't see any of that.
    Also it doesn't tell me if the PSU itself is bad or not.
    The caps probably won't bulge... Look for a greasy stain around them:

    http://i1246.photobucket.com/albums/...tt-k/leaky.jpg

  7. #17

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    Quote Originally Posted by scott-k View Post

    1 Yellow (+12V)
    3 Red (+5V)
    12 Black (GND)
    14 Blue (-12V)

    Ground the green wire on the ATX power supply to turn it on.
    This powers the Mac directly, so you don't need pin 15.
    Guess this would even be easier with an AT psu, i have a few of those, just start the psu and away we go... hopefully.

    Quote Originally Posted by scott-k View Post
    The caps probably won't bulge... Look for a greasy stain around them:

    http://i1246.photobucket.com/albums/...tt-k/leaky.jpg
    Uh oh, i saw a few that i think have leaked, not good :/ never thought those small things were caps tho.

  8. #18

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    HAHA would you look at that, it booted right up with a AT psu, nothing wrong except that the OS is busted but i knew that from before, and as i don't have any OS diskettes i can't fix it, the hd seems ok even with the leaking caps... for now.

    Thanks alot scott-k now i atleast know that the mobo is somewhat ok so i can play with it, maybe i should open up the mac psu and check it's innards to see how it is, also noticed that the traces to the button has started to flake, that might be a reason it's not booting either.

  9. #19

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    Does anyone have the schematic for this mac or know where to find one? trying to figure out of the power button leads are busted, 1 of the 6 pinns seem to be minus and goes almost directly to 1 of the batteries, the other one along side it go to 1 of the caps so i know these 2 work atleast, the other 4 is another matter, i realy can't see where they are going.

  10. #20

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    No one?

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