Currently Being ModeratedMar 11, 2012 8:37 PM (in response to kfdc)
Here's a pic of the back of the switch itself with electrical connections noted.
and a pic of the side you push with the cover off:
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!).
Currently Being ModeratedMar 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'.
Currently Being ModeratedMar 12, 2012 8:57 AM (in response to spudnuty)
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
Currently Being ModeratedMar 17, 2012 11:48 AM (in response to spudnuty)
Thanks so much for all this detail, Spudnuty. Finally got a chance to try again just now, and still nothin'.
I checked the new battery I'd put in about a week ago, it was reading about 3.5. So i put it back in, pushed the PMU reset button firmly for a second then released, waited 10 seconds, plugged the emac back in, 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). Silence.
So then I unplugged it, and in case your last thought about the plastic connector being bad was on target, I cut (reluctantly) the shiny black and red about a centimeter behind the connector, stripped them (on the end coming out of the emac), took the battery out to double check it's level, put it back in, reset the PMU again, waited 10 seconds, then plugged in the emac again and (using my little electronics probe clips so I'd be sure to have a good handle on those little wires) shorted them again. Still nothing.
Even tried shorting them with the battery just removed, and still no luck.
Just found the service manual online, and, assuming my shorting tests are equivalent to trying a new power button, the next steps would be to go in and start checking for power internally: voltage at AC connector, fuse, etc.
Any reason my shorting tests would NOT be equivalent to trying a new button?
Much as I would love to spend the next two days diving into this just for the fun of it, my wife and toddler would probably not be real happy, so I'm on the verge of donating and upgrading.
Thanks in advance for any further thoughts.
Currently Being ModeratedMar 17, 2012 1:11 PM (in response to kfdc)
After posting the above, I found an emac service manual online and plunged into the "No power symptom charts" in the Troubleshooting Section. Assuming my black-red short tests were the same as trying a new power button, I went onward from there and worked my way along (with everything checking out okay) to checking for a "5V trickle on capacitor C3202." Took some searching, but I found it eventually and was unable to get any voltage reading. Even after I realized I needed to have the unit plugged in (ahem). Don't know if there is some trick to taking that reading right: I had my black test lead on metal, the red lead on the little solder pad that extends right out from under the capacitor. got nothing, not even a jiggle of the needle. The manual says if no voltage there, "replace the display/analog assembly", which appears to be basically most of the machine.
Anyone with experience checking for a trickle voltage like that know of any tricks to that I might be getting wrong? Or is it time to offer this baby up for spare parts and move on?
Currently Being ModeratedMar 18, 2012 12:09 PM (in response to 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.