Fun with iMacs...

Post #427,332 by Another Scott 1/29/19 10:35:51 PM 1/29/19 10:35:51 PM Reply	Fun with iMacs... Hi folks, J has a 2011 i7 27" iMac at work running 10.12.6. She's had good luck with it, but a couple of weeks ago it started acting weird. It would spontaneously reboot, or on startup in the morning it would go 50% on the progress bar and then change to a white screen. And then reboot. No problem, I thought, we'll do some checks - it's probably just a bad spot on the 2TB Hitachi hard drive... Hmm. The Recovery boot won't work and it won't boot from a USB. I can't boot from a DVD either. Zap the PRAM. OK, we've got the "booommmm" bootup sound again. Hold Option/Alt key, can see the boot drive and the recovery partition.... (Off and on attempts to get to Disk Utility via the Recovery boot over several days....) What's this? Success!! Run Disk Utility - What? Nothing's wrong??? Run the Apple hardware tests. What? Nothing's wrong??? Oh well, I'll buy a copy of Disk Warrior over the weekend and have it fix things on Monday (yesterday). Hey, I was able to get the Recovery boot to work again and was able to run Disk Warrior!! Yay, it found some things to fix, but they seem really minor (9 icons, and a slightly more serious bitmap issue). Replace the bad xxxx. Ok. Yay!! It booted up! Quick!! Run Time Machine and dump everything to a new external 2TB drive (only $70 at MicroCenter). Let it run overnight. It was still running Ok this morning (backup finished at 11 PM), shut down, and reboot. Starts up fine. Success!!! So, J puts it back on her desk, hooks up her USB hub and wireless Logitech mouse. Everything seems fine, for several hours, she's working on an e-mail and... Blue screen. On rebooting with only apple mouse and keyboard, white screen. It won't boot now. None of the various partially-successful steps earlier work now. Grrr.... In looking around for previous comments on these things, some people were saying it was a graphics card issue, and others were saying it was a firmware issue with the HD. Neither made much sense to me (there was never any sign of video corruption, and all the tests say the HD is Ok). I did some more looking around and found this: https://www.youtube.com/watch?v=zoOchEUPBkI Of course!! I remember an old PC that would have all sorts of issues with rebooting, not booting, etc., because the CMOS battery had died. It's probably dying on the iMac as well - it is nearly 8 years old after all... Of course, I'd have to take the screen off and the LCD display, but it shouldn't be a huge deal... OMFG! As that video illustrates, you basically have to disassemble the entire stupid thing to gain access to the battery!!!!11ONE (I was hoping that the video was of a different model.) :-/ It's still possible it's the graphics card (I haven't verified that it actually is the battery) - but it has all the symptoms of the boot sequence being mangled because the PRAM settings aren't being saved. We really can't justify spending more time trying to diagnose it, but it's a real shame that an expensive computer like this will probably be surplussed because the $3 battery died.... A week ago (when it wouldn't boot) she was able to order a new 5k 27" i7 (the top one just below the iMac Pro), 32 GB RAM, 1 TB SSD. It would be great if it also lasts for 8 years! HTH someone out there. Keep your eyes peeled, Ashton! ;-) Cheers, Scott.
Post #427,333 by a6l6e6x 1/29/19 10:58:49 PM 1/29/19 10:58:49 PM Reply	Wow! Given the time and effort you've put into it, I'm amazed you didn't just go buy a new one. Alex "There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "my ignorance is just as good as your knowledge." -- Isaac Asimov
Post #427,335 by Another Scott 1/29/19 11:22:38 PM 1/29/19 11:22:38 PM Reply	It takes a long time to buy stuff at work. ;-)
Post #427,336 by scoenye 1/30/19 7:06:56 AM 1/30/19 7:06:56 AM Reply	BSOD on a Mac? I feel a patent spat coming on... Silly idea: reseat the RAM (if possible) and HDD (or pull the cables depending on how its mounted.) Those connectors do sometimes develop spotty contact with all kinds of mayhem as the result. And along the same lines: can you test the RAM, or run it with 1 stick at a time?
Post #427,352 by Another Scott 1/30/19 9:13:14 PM 1/30/19 9:13:14 PM Reply	:-) I'll check those things if I find the time to pull the glass and the screen to get access to them. Part of the Apple Hardware tests is a detailed test that exercises all the RAM. It took over an hour (16 GB) but didn't find anything wrong. I'd really like it to be the case that I can resurrect it for the price of a 2032 battery, but it will have to wait until I can find the time to take it apart. (Conversely, I'll be really pissed if it is the graphics board (costs about as much as a whole iMac on eBay...).) Thanks muchly. :-) Cheers, Scott.
Post #427,358 by scoenye 1/31/19 7:43:07 AM 1/31/19 7:43:07 AM Reply	Is there a clock anywhere on the diagnostic screens? PC UEFI/BIOS screens usually have a time display. If the Mac has something similar, that would be a surefire way to check the battery. If the clock is correct, the battery is doing fine. OTOH, if it thinks it is 02/24/1955, the battery is dead.
Post #427,359 by Another Scott 1/31/19 7:46:00 AM 1/31/19 7:46:00 AM Reply	Ah, good idea! I'll try to check. Thanks.
Post #427,390 by pwhysall 2/2/19 9:16:12 AM 2/2/19 9:16:12 AM Reply	iMacs are great while they're working And utter dogshit to troubleshoot and fix when they're not. Both of mine - a white one and an aluminium one - had serious hardware faults. Both fixed under AppleCare. When you get a Mac fixed under AppleCare you get an invoice listing all the parts and their prices, even though it's at zero cost to you. 2nd iMac needed: Screen replaced - £600 GPU replaced - £400 Optical drive replaced - £150 Hard disk replaced - £100 First one had something similar. I wouldn't keep an iMac beyond the warranty period - they're both expensive to fix (parts are just ruinously expensive) and difficult to work with; they're hard to open with several points of expensive failure in the process. If Apple simply stopped the pointless quest for thinness on desktop computers, they could use nice, pretty-much-stock desktop-class components with quiet, effective cooling solutions, in a serviceable form factor. And it'd still look awesome. But at present they're a chimera - odd sort-of-laptop components in a thermally-compromised enclosure that positively encourages failure and is an absolute bugger to deal with when that happens.
Post #427,652 by Ashton 2/21/19 11:21:38 PM 2/21/19 11:21:38 PM Reply	I can aver that.. electronics doesn't Like (any extra ) heat, that assured bugaboo of Bon-Ton-thinness ... and what it costs re any repair but especially (GPU and elsewhere) in these overgrown laptops. I attribute the apparent health of my early/late? '09-24" to just a couple matters I Do pay attention to: A) Make sure to run fingers across the [too-Small] holes in the bottom ... at least weekly; with cat hair grabbing the dust, these are easily hi-𝛀 air-resistance you don't want. I mentioned earlier the unsatisfactory #s on GPU temp and nearby, when I had neglected the finger-test+clean thing, and the before/after-cleaning effect. B) Run latest fan control, [currently SSD] setting usually a bit faster than the OS defaults; the new levels are not screaming (but moving more air == dust in the filter-free teeny holes, too.) These small fans have a copacetic MTBF, and I'll go with the stats. C) Luck Ergo with A B and likely C: I'm alright Jack until ... Timmy decides to stop securitizing Safari. Again. If we're not in caves by then.. lamps burning Republican-oil (stored from the earlier massacrees).

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