Rev A iMacs, yellow power button, and a blank screen... WHY?

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doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1355

It happens randomly, the screen goes blank (like it went to sleep) and the power button goes yellow (like it went to sleep), but I know it is not asleep since I can shutdown the machine by pressing the power button (to activate the on-screen 'restart/sleep/cancel/shutdown' menu and press enter to cause the machine to shut down.

Something is telling the screen to go to sleep and nothing I do will wake it back up (short of a restart by any means necessary). I have repaired permissions, repaired disk, turned off ALL power saving settings, and waved a rubber chicken over the machine while chanting some voodoo gibberish I picked up from a James Bond flick on Spike. Why is the screen going blank on me? How can i determine if this is hardware or software (since it never does this on 9.2.2, only X.2.8, it could be how X interacts with the hardware...).

The problem is more nuisance than anything else, but a permanent fix is desired.

--DDTM

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--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'

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Eudimorphodon's picture
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Joined: Dec 21 2003
Posts: 1203
Analog board failure.

What you're seeing is the classic symptoms. Admittedly, it usually seems to go entirely, rather then sporadically flaking out like you're seeing, but... in all likelyhood your board's on it's last legs, and it's going to die for real sooner or later.

If you're not into ripping the guts out of your iMac, recasing it, and using it with an external monitor, you can:

A: Buy new parts / pay to have it repaired

B: Try this:

http://www.macopz.com/columns/imacrepair/disassembly.html

(Soldering and other nastiness required, of course.)

--Peace

davintosh's picture
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Joined: Dec 20 2003
Posts: 554
That may be the beginning of

That may be the beginning of the end of your flyback transformer, but you may be able to get a few more miles out of it before it's permanently gone. I had an iMac doing that once, and initially I thought it might be a power supply problem, so one of the things I did to try & troubleshoot the problem was to swap the logic board tray out with another iMac that wasn't playing tricks like that; I figured if it the problem component was in the chassis, then the problem would manifest it regardless of which logic board/hard drive was in it. Well, after I swapped them, NEITHER machine showed that problem. And it was at least a year before it started acting up again, and then it was truly the famed analog board flyback transformer death.

From that experience, I'm thinking that the old repair tricks I learned way back when in the Air Force hold true with Macs too. If something isn't working, take it apart, put it back together, and it'll work. It may have something to do with shaking things up a bit, reseating connectors, or PFM... I dunno. But it works more often than it ought to if it were just a fluke.
--
dave

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doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1355
Major hack in the planning stages anyway...

Well, I am in the planning stages of a MAJOR hack to my Bondi. I am getting a new case from davintosh and a couple dead Rev A's from a local source, I also have an older Apple Monitor on hand and plans to aquire a dead Lombard. I am seeking a special part to adapt the LCD from the Lombard to the iMac and may have just located it.

The end result will be the Lomabard LCD hacked into the iMac case with the stock iMac MB and chasis, a pair of 120 GB HDs will be located in the upper part of the case. My CURRENT hardware config is the standard Rev A, with 512MB RAM, 6MB video RAM, 24x internal CD-RW (slot loading), the stock 4.3 GB HD, and a 120GB HD (Maxtor) - both HDs connected to same IDE cable and located external to the case. My hack will locate both of these drives to the internal of the case. If I can locate the right parts, I may try to drop a second CD/DVD drive in. This is all contingent upon my locating an affordable VGA to LVDS converter for the Lombard LCD to work. Depending on the severity of the flyback transformer, I may have to swap some parts for now to hold it together. It all works on paper, I just need to gather the right stuff and build it.

The extra cases, may be turned into dumb monitors for desktop mirroring or extended desktop for another machine (unless I can hack the ATI chipset on my Bondi).

Thanks for the tip.

--DDTM

if it ain't broke... break it anyways so you can justify taking it apart!

__________________

--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'