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Level 6

13,226 points

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

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.

Worst case scenario: early warning of dreaded failing PAV board? Or is this simply a mechanical malfunction in the switch, possibly some dirt or even corrosion in the contacts which could be cleaned with contact cleaner? A failing relay? I thought it might even be the angle at which I apply pressure to the switch.

What's involved in getting to that switch, including replacing?

Also, if this is a mechanical problem with the switch, could it be bypassed using a different keyboard with a power switch key? And, if so, which keyboard would I have to find?

Anyone ever see this one before? (Just did a search and don't see anything more recent than 10/01/09 for Spudnuty, the iMac G3 master. Hope he's still around.)

Message was edited by: WZZZ

iMac G3/400 OSX 10.4.11 "It takes a licking and keeps on ticking", iMac G5/1.6 OSX 10.5.7

Posted on Oct 28, 2009 6:43 AM

19 replies

WZZZ Author

Level 6

13,226 points

Oct 31, 2009 4:29 AM in response to spudnuty

Hi Richard,

Many thanks for all the help and for taking the trouble to post those pictures and links. I guess I'll have to open it up--as soon as this G5 nightmare ends--and see what the state of that actuator is.

For the G5, I'm at least hoping they're using parts from a production run after they discovered the defective caps issue, or that they did refurbs on the originals. I guess I can always hope.

For what it's worth, my two cents: Since they would lose money, time, and reputation, I would imagine the shop (an authorized shop here with an excellent reputation) that's been working on this wouldn't want to do these repairs if they knew they were getting defective parts. And I can't imagine they wouldn't know. But, if these parts have been hanging around for a few years, I believe those electrolytic caps could go bad just from aging, not being used. Maybe that's what's been going on.

BTW, maybe you can explain the pop I heard--total two times now before these shutdowns--just before the latest, unexpected shutdown. (Last one had log entry of "AppleSMU -- shutdown cause = -110") Someone, elsewhere, thought exploding cap inside the PS (all the logic board caps look good), but I didn't and don't smell anything even when close to the PS.

Rod Hagen

Level 7

32,000 points

Nov 4, 2009 3:39 AM in response to Kenichi Watanabe

Hi Kenichi,

This takes my memory back to queries raised in the early days on the Apple discussion boards, but the slot loading Summer 2000 iMacs and onwards that came originally with the "Apple Pro" keyboard and mouse can't be booted using the power button on the earlier "Apple USB" keyboard. They simply lack the necessary circuitry for keyboard power booting - see http://support.apple.com/kb/TS2222.

The last iMacs that could be booted in this fashion were the very first 'slot loaders, that came with the early keyboard and "hockey puck" mouse as standard.

Cheers

Rod

Rod Hagen

Level 7

32,000 points

Nov 4, 2009 4:08 AM in response to WZZZ

WZZZ, as far as the capacitor issue in iMac G5's goes, the replacement power supplies and motherboards should be fitted with the "K" style caps, rather than the one that were originally fitted (and caused so many of us much pain!)

For a good cost effective solution to the G5 issues, and quite possibly also for your iMac G3 power switch, I'd try Michael Lafferty at http://www.synaptech.com. Not 100% sure that he still offers the service, but they used to be able to replace defective motherboard caps at far less than the cost of a replacement motherboard for the iMac g5's. He also stocks power supplies.

Cheers

Rod

WZZZ Author

Level 6

13,226 points

Nov 10, 2009 3:38 PM in response to Rod Hagen

I don't know if anyone's looking at this thread any longer--I just returned by chance to see Rod's post--but I'm getting quite a mixture of opinion on what the "good" caps are supposed to look like. Some say K; some say Y; some say the scoring pattern is completely irrelevant, someone said the bad ones had a copper stripe and the good ones a gold stripe.

My logic board is a "new" Apple replacement. It's got a mixture of Xs and Ys. I'll probably just have to wait until this thing craps out on me again to know for sure.

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