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G3 iMac (slot) I have is switching itself off.

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G3 iMac (slot) I have is switching itself off.

by Gibsaw » Mon Nov 23, 2015 1:29 pm

Soooooo... a slot loading G3 iMac I have is switching itself off. This varies between a few minutes and a couple of hours, until which it works fine.

Solutions I have had suggested vary between: reset the PRAM ...to... replace the PRAM battery ...to... replace the RAM ...to... Replace/Repair the PAV (power/analogue/video board)

It does have 3rd party RAM and hard disk installed, but they work flawlessly as long as the machine is on.

It loses date if I switch off, so I know for a fact the PRAM battery is dead as a doornail. I'm going to replace the battery, but I definitely get the feeling that reset of the PRAM is the mac world's "sprinkle some fairy dust and repeat there's no place like home" solution to mysterious niggles... Or am I wrong? Is it that much a factor in power-state sillyness?

Am I likely to get any joy from PRAM related fixes? Or do I have a PAV repair to do? Any comments? (It's a pain to remove, involves an HT discharge :shock: , and CRT recalibration. It wouldn't be my preferred outcome. :? )
"dsakey" on trademe. Apple II's are my thing.
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Re: G3 iMac (slot) I have is switching itself off.

by Audronic » Mon Nov 23, 2015 8:22 pm

@Gibsaw

Command-Option-P and R --- Pram Reset hold for 3-4 Boings
Command-Option-O and F ---- Open firmware reset
Using :- reset-nvram (Enter)
set-defaults (Enter)
reset-all (enter)

and see what happens.

Good luck

If you are ever over in Australia come and pickup SOME (For you ONLY $0.01 Aus Dollars) Thats 1 Cent.

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Re: G3 iMac (slot) I have is switching itself off.

by Gibsaw » Tue Apr 05, 2016 11:42 am

Yes, I have had the feeling that iMac G3's are so common that they'll be in scrap piles for a while.

Trouble is, the same could be said of the MILLIONS of beige box x86's (286/386/486). No-one cares. They've all gone to recycling... But try finding one now. I suspect the iMac G3 will end up the same. And I notice they are all dying of the same thing. A PAV board fault that seems to be ubiquitous but I can't find a commonly documented repair. It always seems to be "replace the PAV board" - which will end up with a lot of scrapped G3's and no working PAV boards left. :?

...and while I'm bitching about x86... :) I know they've all gone to recycling, but what's with the prevalence of ugly desktop cases in vintage kit?!! Where the hell did all the minitowers go?!!!
"dsakey" on trademe. Apple II's are my thing.
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Re: G3 iMac (slot) I have is switching itself off.

by tezza » Tue Apr 05, 2016 5:17 pm

Gibsaw wrote:Trouble is, the same could be said of the MILLIONS of beige box x86's (286/386/486). No-one cares. They've all gone to recycling... But try finding one now.

You're not wrong there!
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Re: G3 iMac (slot) I have is switching itself off.

by SpidersWeb » Wed Apr 06, 2016 8:07 am

My G3 tower has power up issue as well. It doesn't turn itself off but has trouble getting started. My plan was to locate the latching circuit on the motherboard and replace some caps, but haven't got around to it yet nor investigated it. In the PC world you'd just link green to black and see if the issue went away, but not sure if that also applies to G3 era Macs or not.

Just mentioning it in case it inspires any ideas at your end.

I think the G3 era machines are worth collecting - very unique styling and engineering.
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Re: G3 iMac (slot) I have is switching itself off.

by Audronic » Wed Apr 06, 2016 11:29 am

@SpidersWeb

The intermittent power up from cold usually is that the Battery has gone flat.
as you haver the power on for some minutes a small amount seems to trickle into the battery area and then it will start.

Try a replacement battery

Good luck
Ray
Last edited by Audronic on Thu Apr 07, 2016 10:49 am, edited 1 time in total.
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Re: G3 iMac (slot) I have is switching itself off.

by SpidersWeb » Thu Apr 07, 2016 8:13 am

Cheers, will do.
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Re: G3 iMac (slot) I have is switching itself off.

by Gibsaw » Fri Apr 08, 2016 11:31 am

My situation is the opposite. The battery is dead flat, and sometimes I need to reset PRAM... but it usually starts fine.

Until it gets warm. Then it just randomly switches off - and by switches off, I mean goes into a funny power state where it's not working, and I have to hard poweroff to reset it. Very odd.
"dsakey" on trademe. Apple II's are my thing.
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