iMac G3/400 slot- power switch question (Spudnuty?)

Sometimes i have to press the poweron button twice and on occasion thrice. I tend to hold down the button until I hear the electric sound.

The battery is dead on my machine. I have the time set from an atomic clock on the net.

How is your battery?

Robert

If it's the switch itself, using the power button on the keyboard should work without the problem.

The original iMac (smaller size) USB keyboard has a power button. The first larger size USB keyboard from Apple ("Pro" keyboard) did not have a power button. The original iMac keyboard should be readily available on eBay.

The Macally iKey, which is a full-size keyboard that is similar in feel to the old Apple Extended Keyboard II (ADB)

http://www.macally.com/EN/product/ArticleShow.asp?ArticleID=149

has a power button. I'm surprised they still sell it. It may be available for less from a reseller. I have an old blue one.

You can also try this procedure to reset the PMU

http://mrjcd.com/junk/PMU.jpg

As stated, be sure to only press the button ONE TIME between startup attempts.

The picture shows it being visible next to the RAM slots, so you should be able to reach it through that opening. I'm more familiar with the older tray-loaders, where you have to pull out the internal chassis to reach the "cuda" button (as it is called on that model). Often, the PMU button press resolves the problem where the iMac G3 will not start up at all (no sign of power). In your case, since it does start up sometimes, pressing the PMU button may not help, but it wouldn't hurt to try (as long as you press it just one time between startup attempts).

Hey W,
Yup haven't been around much. Had a lot going on.
Here's a pic of the power button on the front bezel of a G3 iMac:
http://s291.photobucket.com/albums/ll306/spudnuty/?action=view&current=iMacpower button.jpg
The gray plastic that these are made of can crack and seems to be prone to that over the years. However you see this more in the upper part of the front bezel which is subject to more heat.
If you take the bottom off the machine you can check out the action of the inner actuator (the part you see in the pic).
The "actuator" part is pressing on a tactile swich which is on a small sub board that is mounted on the frame. It's a little hard to harvest but I do have a lot of non working G3s if that turns out to be the source of your problem.
Also sometimes the outer part of the power button will get sticky.
As to the keyboard button I've got a iMac G3 350 (OS 9.2.2) a 400 (10.4.11) and a 600 (10.4.11) and can't get the original Bondi or a Strawberry keyboard to work with them. I don't have a later keyboard however and all the later ones don't have that power button.
The repair manual says it will work on the 400 and SE but I do seem to remember about this never being enabled.

Over the last several months I've sometimes had to press the power switch maybe three or four times before the computer starts up. And sometimes, less frequently, it takes a few presses to get the computer to sleep. When it sleeps, it sleeps fine. It might boot up directly with one press for several days.

After it boots up, it boots up fine and stays booted until shutdown at end of day. No green or dimmed or funny looking power light; absolutely no problems. So, can't rule it out, but don't think these are symptoms of the PAV board.
Doesn't seem like the PAV board but you can never rule that out w/ these machines.
Check out the part in the pic and post back.
Richard

According to LowEndMac's profile page, if your iMac G3 400 MHz is +Summer 2000+ (or later), it shipped with the Pro keyboard

http://www.lowendmac.com/imacs/400-mhz-imac-dv-g3-2000.html

Other Internet references say the Pro Keyboard was introduced in 2000, so that makes sense.

Therefore, the earlier slot-loaders from 1999 came with the smaller iMac keyboard with a power button, so it should work on that model. If your iMac is the darker shade Indigo or Ruby color, it is from the 2000 line, so I suppose it is possible that power button will not work since they shipped with keyboards that no longer had the power button.

Hey W,

From that photo, it looks like the "actuator" is rather small and located on one side of the button. Perhaps that would mean that applying pressure on one side or another--one of my theories-- might make a difference. If that piece has broken off completely, I'd imagine I wouldn't be able to start up at all.

What might have happened is that the actuator part is cracked or broken. In my experience that part is quite brittle. The one you see is the only intact one I was able to remove out of 3. All the rest cracked.

Not any easy place to spray contact cleaner

And it wouldn't help anyway since that tactile switch is sealed al la:
http://tinyurl.com/yl2ozfj
I'd take the bottom off (4 screws) and check the state of the inner switch.

Incredibly bad luck with Apple replacement parts: New, but defective logic board from Apple--this has been replaced--and now, very likely, a new, but defective Apple power supply, which will also need replacing.

Yes all those parts are from the original production run and contain the same defective capacitors that were in thousands of computers made at that time: Dells, Sonys, HPs etc. We had about 20 Dell P-4s go bad with that cap problem at the school. My current fix is either Jim Warholic caps or a hacked Flex Micro ATX and auto adapter replacement.
Richard

I didn't say it would not work on later G3 iMacs. Just pointing out which ones shipped with the older small keyboard. 🙂

Note: Even on current Macs, if you use a keyboard with a power button and press it when the Mac is powered on, you get the dialog box with +Restart, Sleep, Cancel, Shutdown+ (but the button is not recognized if the Mac is powered off).

Came across this device, and the description (if it is accurate) indicates that "iMac DV Summer 2000 or later" cannot start up from a power button on a USB device.

http://www.welovemacs.com/usb-key-bt.html

So I guess it won't help to find a keyboard with a power button.

W,

Are you certain that's what they're using for current repairs?

Well I can't imagine that any manufacture would still be making new parts for a machine that's multiple generations old. They'd go broke.

the caps look good now--I noticed they looked awfully similar to the ones on the original board that went bad

When they fail there can just be the least little doming of the top. An ESR meter would confirm the failure.

I've heard replacing the caps in the PS doesn't always help since there's often collateral damage to other parts inside.

My success rate is 1 out of 4 and that's exactly what happened.

I've heard the iSights are not plagued by this problem, just the early generation

Yes those bad caps were during a certain period.

Eventually, if that little tab breaks off--assuming that it's cracked--no power up?

Yup that's why you've got to open it up. It is possible to replace the inner button or sub board.
Richard