taz3599

Q: eMac doesn't boot consistently

Hi, I recently repaired a few eMacs and gave them new logic boards and repaired their HD's.  I had them all up and running again but one of them now will not boot up consistently.  It may boot up completely once if I leave it unplugged for a few hours, but if it is restarted or shutdown only a black screen will show and the front led light will be off half the time and normal the other half of the time.  Same goes with the boot up chime, it is there only about half the time.

 

I know the battery was bad so I replaced that with another working one from another logic board, but it had no affect on the machine.  Resetting the PRAM and pressing the CUDA button do nothing.  The first time it had acted this way was when i had the Apple Hardware Test CD in and was doing a full scan of the machine.  It froze during the test so I had to restart the machine and all I got was the black screen.  I haven't seen an eMac do this before and was wondering if you guys had any advice on what could be the problem or what steps should be taken next.

eMac, Mac OS X (10.5.6)

Posted on Jun 18, 2011 1:00 PM

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Q: eMac doesn't boot consistently

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  • by Allan Jones,

    Allan Jones Allan Jones Jun 18, 2011 4:19 PM in response to taz3599
    Level 8 (35,039 points)
    iPad
    Jun 18, 2011 4:19 PM in response to taz3599

    First, is it a 1.25Ghz model? If so, check the serial number of the offending machine against the serial number ranges I posted in this thread:

     

    can't upload content on emac or burn cd's                   

     

    The logic board issue with the affected can produce a dizzying array of very odd issues.

     

    If the machine is in one of the ranges, post back here, not in the other forum.

     

    Aj

  • by taz3599,

    taz3599 taz3599 Jun 18, 2011 4:37 PM in response to Allan Jones
    Level 1 (0 points)
    Jun 18, 2011 4:37 PM in response to Allan Jones

    No it isn't a 1.25 it is a 1Ghz model.  I have another 1GHz board here that I will switch out with this one to see if that would work, but I am waiting on a 512 stick of ram to be shipped here.  I was hoping maybe there was something I was missing so I could just fix this issue and save me time, but if not I can only hope this other board will work.

  • by Allan Jones,Helpful

    Allan Jones Allan Jones Jun 18, 2011 7:40 PM in response to taz3599
    Level 8 (35,039 points)
    iPad
    Jun 18, 2011 7:40 PM in response to taz3599

    "No it isn't a 1.25 it is a 1Ghz model."

     

    Might want to check the LB before you swap because there was an uncataloged "edu-only" version with the USB 2.0 logic board of the 1.25Ghz and 1.42Ghz eMacs, but with a 1.0G processor. They were also affected by the bad cap issue.

     

    With a bare board, the best way to tell the difference between the common 1.0Ghz USB 1.1 LB and the rarer 1.0Ghz USB 2.0 board is to count RAM slot contacts. The USB1.1 version used PC133 RAM and the USB2.0 board used PC2700.

     

    References to the edu-only eMac with a 1.0Ghz cloc k and USB 2.0 are herd to find but it is here:

     

    http://www.everymac.com/systems/apple/emac/stats/emac_1.25.html

     

    in fine print.

  • by taz3599,

    taz3599 taz3599 Jun 18, 2011 9:22 PM in response to Allan Jones
    Level 1 (0 points)
    Jun 18, 2011 9:22 PM in response to Allan Jones

    Thank you for that information on the "edu-only" version, I had not heard of this and it is in fact one of those.  I knew the RAM was different and I had to order that separately because I couldn't find it on any of the other ones but I did not realize why.  There were bad capacitors on the boards that I replaced but I have replaced and re-soldered new capacitors on the LB and the power supply.  I have wanted to try the soldering job out but like mentioned before, I could not find the right RAM needed on any of the other boards.

     

    So I will put the original LB back into the machine when my RAM comes and hope my soldering job worked and that it will bring the machine back up to working condition.

     

    Once again thank you for your help and knowledge of this "edu-only" LB.

  • by Allan Jones,

    Allan Jones Allan Jones Jun 19, 2011 9:14 AM in response to taz3599
    Level 8 (35,039 points)
    iPad
    Jun 19, 2011 9:14 AM in response to taz3599

    "Once again thank you for your help and knowledge of this "edu-only" LB."

     

    You are very welcome! I'm glad that was useful. I've been accused of being a wellspring of useless trivia--at least that bit was kept for a reason!

     

    If you are comfortable repairing the LBs, you could have a mini-career! Apparently, a lot of eMac owners who had the affected machines did not get the word on the Repair Extension Program and sloughed off the computers when the symptoms arose, or the symptoms did not appear until after the REP expired in June 2009.

     

    There is a shop in Oregon that has done a cap replace service on eMacs for much less than the cost of a new LB. The problem with the repair service was that it behooved you to be within driving distance because the cost of shipping a 50-pound eMac both ways added close to US$100 to the bill!

     

    BTW, have you seen the info that the USB2.0 eMacs, with modern modules, can hold and access 2G RAM? We have one 1G stick plus one of the original 256MB sticks in our 1.42Ghz eMac--a total of 1.25G RAM--and it's completely stable. "Just any" 1Gig PC2700 or PC3200 modules won't work. I bought ours from OWC (www.macsales.com), a Mac-savvy vendor who actually seem to test stuff before they sell it. Refreshing!