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Thread: 5260 power problems

  1. #1
    Join Date
    Oct 2001
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    Grass Valley, Ca. USA
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    I have a 5260/100 power mac that sometimes will boot and other
    times it will not. It is a progressive thing, where the machine
    will boot just fine the first time and maybe a few times but it
    eventually will only try to start (lights flash across num lock
    etc. and the hard drive tries to kick in). It will do this for
    a few times until, finally, there is no indication of any power
    going thru the keyboard or into the machine.

    I have reset the logic board with the same results.

    I have put the hard drive in another machine and it starts that
    machine consistently.

    How do I determine if it is the power supply (do power supplies
    act like this, or do they either, simply work or not work?), or
    if it is the logic board or analog board?

    I have manuals to do the take apart and am aware of the CRT
    voltage issues, but am not sure how and where to test the
    various modules?

    Any help would be greatly appreciated.

    Tom L.

  2. #2
    Join Date
    Jan 2001
    Location
    Austin, TX, Los Estados Unidos de Mac
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    Well, I've never handled a Mac such as yours, but it sure sounds to me like a PRAM battery problem. Guys, does it sound like I'm right on this, or am I off the mark?

    If it is the PRAM battery, it's a simple matter of locating where it's installed on the motherboard, figuring out which kind it is, and heading off to Radio Shack to get a replacement.

    If it's not the battery, I would next suspect the power supply, but again I'm not completely sure. I bet someone who knows a little more than I do about those all-in-one Macs will be along to help out here shortly.

  3. #3
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    I think you are right on, t_a. At least it is a good place to start. Unfortunately I don't believe Radio Shack carries the right battery for this one. You need a Battery Type: 4.5V alkaline. Your local Mac shop should have it. k

  4. #4
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    Oct 2001
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    Grass Valley, Ca. USA
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    Thanks for the response. I forgot to mention that I have already
    changed the battery. As for the PRAM reset, I believe that it
    is reset when the logic board is reset (i.e. unplug the battery
    for at least 10 minutes and press the cuda chip reset button and
    hold it down for about 15 seconds).

    Thanks again....any other suggestions out there?

  5. #5
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    Try another keyboard. Sometimes something goes wrong with the switch under the Power key and the result is unpredictable things happen. Also, if you have an ADB extension cable between the keyboard cable and the computer, try removing that. k

  6. #6
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    Your symptoms seem to indicate that your power supply is on its way out. The fact that it progressively gets worse as the system warms up is a good sign. Of course, it could also be something on the logicboard that's heat sensitive as well, but the power supply is a more likely bet. Being that everything is internal on the 5260, makes diagnosing the problem a bit more tricky. If you've got any other 52xx, 62xx-65xx Macs, you could try swapping logicboards to see if the problem swaps as well.

  7. #7
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    Oct 2001
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    Thanks for the replies. I have already done all of the quick fixes
    such as switching power cords and keyboards etc. I am pretty sure
    that it is the power supply and/or logic board, and was hoping that
    there was a way to test these without swapping parts. I occassionaly
    come across other 5260's but do not have one available at present.
    I do, however, have a 5500 and wonder if I could use that logic
    board in the 5260 to test the power supply in the 5260. That would
    narrow it down to one or the other (p.supply/l.board). Any thoughts
    on switching the logic boards on these two? I'm sure the processors
    are quite different, but do not know if they are otherwise compatible.
    They will fit in the same slot.

    Thanks for the help.

  8. #8
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    Jul 2001
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    I believe the 5500 logicboard requires an additional voltage line (3.3v?). But, you could install the 5260's logicboard into the 5500 without problems.

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