1.42 GHz eMac not turning on?

Discussion in 'PowerPC Macs' started by appleish19, Feb 4, 2016.

  1. appleish19 macrumors regular

    appleish19

    Joined:
    Dec 4, 2014
    #1
    Hey everyone,
    My 2005 1.42 GHz eMac is suddenly not turning on. It's been working fine for months no issues whatsoever. Turned it off and it won't turn back on. I replaced the PRAM battery but no luck. Any ideas or troubleshooting tips?

    Thought I read that there is a reset switch for the power system somewhere inside? Any tips on that?
     
  2. appleish19, Feb 6, 2016
    Last edited: Feb 6, 2016

    appleish19 thread starter macrumors regular

    appleish19

    Joined:
    Dec 4, 2014
    #3
    Finally got around to trying this. Replace the PRAM battery and reset the PMU. Still no luck. Any recommendations?
    --- Post Merged, Feb 6, 2016 ---
    I am guessing this is the PMU.
    This is also the ram could it be causing the problems. It's not PC 2700 333mhz
     

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  3. Daniël Oosterhuis macrumors 6502a

    Daniël Oosterhuis

    Joined:
    Jan 10, 2016
    Location:
    Black Mesa Research Facility
    #4
    I don't think a PRAM battery being dead disturbs the machine in such a fashion. My iMac G3 has a dead PRAM battery, but it just results in the date being forgotten upon boot. This can be a sign of PSU/CRT Flyback Transformer failure. Do try resetting anything you can though, but if that's the case, you need to do some extensive disassembly and resolder work, definitely not for the faint of heart. I'm going to crack open a dead Indigo iMac G3 I have and try to replace all through-hole capacitors in the hope that that fixes the issue, and that the flyback is not at fault. The capacitors were made in the mid of the capacitor plague. That meant they were very prone to failure. Now if that wasn't bad enough, the fact that all the heat comes past the PAV board (power and analog video board) meant the caps were under extreme stress. The omission of a fan made that worse. I really do hope you can get yours to work again, but these situations just make me extremely sad. They're so hard to recap and to get new flyback transformers for, and the costs and effort go beyond the value of the machine. But I don't want to throw another one away or repurpose it, I want them to work, dangit!
     
  4. MacCubed macrumors 68000

    MacCubed

    Joined:
    Apr 26, 2014
    Location:
    Florida
    #5
    Dead PRAMs will render a TiBook useless, and some PBG3 Pismos too.
     
  5. appleish19 thread starter macrumors regular

    appleish19

    Joined:
    Dec 4, 2014
    #6
    Well I'll have to see if there's any Apple repair places near here. I'm not comfortable working around the CRT myself. So strange because it never showed any signs of problems until one day when I went to turn it on it just wouldn't go. Replaced the battery and pushed the reset button. Nada
     
  6. Daniël Oosterhuis macrumors 6502a

    Daniël Oosterhuis

    Joined:
    Jan 10, 2016
    Location:
    Black Mesa Research Facility
    #7
    These kinds of issues can happen both spontaneously, or start to slowly build up. As for the PRAM, I guess it can disturb machines in such fashion, but I still have my doubts that the eMac wouldn't boot, because I've seen YouTube videos about eMacs, which also had a dead PRAM, but they booted, simply giving an error that the date and time was forgotten and reset.
     
  7. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #8
    I have 3 of those eMacs. Two always work very well. I have one that has two issues. One is a flaky power button. You can't just push it in the center, but it takes pressure on one side before it will work.
    The OTHER issue, which is just annoying, is that every few months there is a power failure - for one reason or another. The logic board locks up, requiring opening the door on the bottom and pressing the PMU reset button (just once.)
    Between the PMU reset, and the possibility of a power button that doesn't quite work right - that should get you going.
    If no luck, you should remove the rear housing (opening the case), take off the "faraday plate" - which covers the logic board. That will allow you to inspect the various capacitors, looking for leaking or swelling capacitors - very common on these. Also, for power problems - look carefully at capacitors in the down convertor board. That's the main power supply for the logic board, and has several of those can capacitors, very closely mounted. You might find leaking ones in there, too. Any problems that you see can give you various system problems, along with power issues.
    Good luck~!
     
  8. Daniël Oosterhuis macrumors 6502a

    Daniël Oosterhuis

    Joined:
    Jan 10, 2016
    Location:
    Black Mesa Research Facility
    #9
    Failed capacitors can sometimes not show signs of failure though. I've seen a fair share of them that looked fine, but in an ESR meter (this device checks the ESR value of a capacitor, which determines whether it is working right or has failed) they came out as total lemons. That's why I'm going to check all caps in my iMac G3 Indigo before assuming flyback issues.
     
  9. appleish19 thread starter macrumors regular

    appleish19

    Joined:
    Dec 4, 2014
    #10
    Thank for the detailed reply. The power button seems to like to push down more on one side. I did realize the power socket on the computer is a bit loose.

    I have tried putting the battery in twice and resetting the PMU (it's the circular button in the square? Above in picture) maybe I'll have to get a hex wrench out and take the cover off.

    Of course my 1Ghz model is always working. Just love the graphics card and core image support of the 1.42.
    The caps look good from the access door.
    --- Post Merged, Feb 6, 2016 ---
    Unfortunately I don't have that type of electrical experience or space. But am going to look into it. Thanks.
     
  10. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #11
    You can only see 5 or 6 caps from the access door. There is another 12 or so on the logic board, several inches beyond the access door opening - plus another 5 or 6 on the down converter board. You _must_ open up the case if you want to inspect those. It doesn't really require technical expertise to see brown goo oozing from the top of a capacitor, or just a swelling top. If you can SEE that, it can certainly contribute to your issues. Then, you get to decide if you want to pursue a repair (it will eventually quit completely).
     
  11. appleish19 thread starter macrumors regular

    appleish19

    Joined:
    Dec 4, 2014
    #12
    No I can definitely do that type of visual inspection. . I'm just talking about using a multimeter electric meter or any type of soldering. I guess I need to learn though :)
     
  12. 128keaton macrumors 68020

    128keaton

    Joined:
    Jan 13, 2013
    #13
    Yup. I got an almost mint 500Mhz TiBook with 512MB of RAM and an AirPort card for $20, since it wouldn't boot. Just unplugged the PRAM battery and *bong*
     

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