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eMac power button workaround

1881 Views 9 Replies Latest reply: Mar 20, 2012 5:58 AM by kfdc RSS
kfdc Calculating status...
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Mar 5, 2012 4:42 PM

Hi,

My emac is a 2003 model, 1Ghz processor, and the power button kept getting dodgier and dodgier over the last year or two, so I started just leaving the emac running and/or relying on the scheduled wake-up to start it.  Then my two-year old decided to shut off the power strip it was plugged into recently, and the battery is dead, so the scheduled start wasn't happening, and the button just wouldn't turn it on.  I took the shell off to check out the power button, and when I tried to push the button through the ring it sits in the button and the little disc of circuit board that's part of it separated from the rectangular plastic connector piece that connects it to the cable.

 

I found an archived thread in this community that addressed bypassing the button, with solution identified from another site as follows:

"The only way to turn it on now is to place a wire (I used a wire twist tie.) that connects the Black and Red leads on the connector for the power button. This is done by placing the wire on the top of the connector where you can see metal showing. This will turn on the Mac."


"Spudnuty" on this site then agreed as follows:

"You have to strip the wire and plug it into the red socket and short it to the black. You can also access these at the exposed locking tabs on the side of the connector. Connections are electrically made."

 

I've tried this with no luck.  First problem is the cable to the power button has two black wires (one narrower and shiny, the other slightly larger and dull) and one red (narrower and shiny).  But I tried shorting all combinations and nothing seems to be turning the thing on. 

 

Does that mean my problem is more than the power button? I had the shell still off when I was trying this - is there some kind of safety system keeping it off when the shell is off?  I'm loathe to spend $40 on a new emac button when something for $3.50 from radio shack to short two wires will do the trick.

 

Any suggestions are welcome.

Thanks,

kfdc


eMac, Mac OS X (10.5.8), 1GHz, 2003
  • spudnuty Level 5 Level 5 (5,250 points)
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    Mar 11, 2012 8:37 PM (in response to kfdc)

    kfdc,

    Here's a pic of the back of the switch itself with electrical connections noted.

    http://s291.photobucket.com/albums/ll306/spudnuty/?action=view&current=eMacSwitc hcircuitboardback.jpg&jwidget_action=album

    and a pic of the side you push with the cover off:

    http://s291.photobucket.com/albums/ll306/spudnuty/?action=view&current=eMacpower switchactionside.jpg&jwidget_action=album

     

    As I recall the shiny black wire is a shield lead, dull black is ground and the red is B+.

    You can tell by the way they're connected to the back of the power button.

    BTW as I recall the wire I used to do the shorting on the female plug from the eMac was a single strand of wire teased from an 18 GA stranded wire. That thing is teeny!

     

    Also this is from the service manual for the 800-1GHz model. The other was the 1 and 1.25 GHz.

    "9 Verify the battery is good before replacing modules. A drained battery may be indicative of a

    crashed Power Management Unit. Does the battery measure at least +3.5v? If not, replace

    the battery and reset the PMU (see next step)."

     

    "5 Touch the metal surface inside the computer. Then unplug the power cord.This helps protect the

    computer from damage caused by electrostatic discharge. Important: To avoid electrostatic

    discharge, always ground yourself by touching metal before you touch any parts or install components

    inside the computer. To avoid generating static electricity, do not walk around the room until you have

    finished the procedure and closed the computer."

    "6 Press the PMU reset button (shown below (It's to the right when the PRAM battery is to the left-spudnuty)) once and then proceed to step 7. Do NOT press the

    PMU reset button a second time because it could crash the PMU chip.

    7 WAIT ten seconds before connecting the power cord and powering the computer on. If the

    computer powers on, go to the next step. If the computer does not power on, there is something

    else wrong with the computer, refer to the symptom/cure, “No Power” in this chapter."

     

    The other problem could be that that connector assembly is bad/broken. It's very easy to damage that little lead when you take that outer  case off (Did that!).

    Spudnuty

  • Allan Jones Level 7 Level 7 (29,575 points)
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    Mar 11, 2012 10:38 PM (in response to spudnuty)

    Good to see you back, Spud!

  • BDAqua Level 10 Level 10 (114,740 points)
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    Mar 11, 2012 10:52 PM (in response to Allan Jones)

    Ditto!

  • spudnuty Level 5 Level 5 (5,250 points)
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    Mar 12, 2012 6:48 AM (in response to BDAqua)

    Gee thanks for the nice welcome guys.

    We moved from Chicago to S.E. Idaho a year and a half ago. We're on 2.25 acres and I now administer 80 PCs (ecchhh) at the Charter School here. So in the first case I'm living up to my handle and in the second I've got a mountain of Dells that I'm repairing. The last 20 or so suffer from the capacitor plague so I bought a bunch of new caps from Mouser and am now wading through the logic boards. As a note on that and since the cap plague also relates to the eMac; I've not been pulling the caps completely, just heating them enough to raise them up about 1/8 ". The electrical connection isn't broken and I can then hold the leads on the top of the board steady as I lever the bad leads out of the old caps. When I have enough of the old leads exposed I clip them off as close to the body as possible. Then I just tack solder the new caps to the stubs that are sticking up. It's not as elegant as pulling the old ones completely but a lot simpler since I have around 40 more bad ones to pull.

    So I'm here but in a much different situation. I still respond to emails tho'.

     

    Richard

  • Allan Jones Level 7 Level 7 (29,575 points)
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    Mar 12, 2012 8:57 AM (in response to spudnuty)

    spudnutty wrote:

     

    We moved from Chicago to S.E. Idaho

     

    We're only about 8-10 hours away (drive 5.5 hours to Boise and turn left, ya know). I think that makes us neighbors out here!

     

    Hope you can pop in from time to time, Richard. There have been some iMac G3 questions that have made my brain hurt!

     

    I now administer 80 PCs (ecchhh) at the Charter School here.

     

    I feel your pain, but on a smaller scale. I volunteer at a Museum at Hells Gate State Park and, because I can spell "computer," have been elected the guru of three Windoze computers in the Center. I've never owned a Windoze computer so, instead of using "trial and error," I'm using the "choke and chunder" method of maintenance

     

    Allan

  • spudnuty Level 5 Level 5 (5,250 points)
    Currently Being Moderated
    Mar 18, 2012 12:09 PM (in response to kfdc)

    kfdc,

    >then tried again shorting the shiny black and shiny red wires (those were the two to short, yes?  ...assuming I don't want to short red to ground, which is what you said the dull black was, which sounds right).

    Actually you're pulling (I think) the base of a transistor to ground so it shouldn't make a difference. It's not like your shorting B+ to B-.

     

    >The manual says if no voltage there, "replace the display/analog assembly", which appears to be basically most of the machine.

    Actually the "display/analog assembly" is the upper part of the machine, sometimes on two boards on the right and left.

     

    >Or is it time to offer this baby up for spare parts and move on?

    There are a lot of eMacs available on Craig's List if you're near a large city. I see 3 on the Chicago site. Prices from $25 to $100. Last seems high.

    Richardd

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