How accurate are apple hardware test?

macguy93 said:

Hello everyone,

if there was something wrong with my computer could there still be a possibility that the test at apple couldn't have picked it up?

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Yes! A very large possibility. Perhaps even tremendously large.

About 18 months ago I upgraded my 2009 Mac Pro to 64 GB of RAM. And all hell broke loose. I repeatedly tested the RAM with various diagnostic apps including Apple's own diagnostics. I then sent the chips back to MacSales for exchange...and tried again. But NOTHING could stop me from crash, crash, crashing. Kernel Panics galore.

So I sent the RAM back and decided I'd have to "settle" for a mere 32GB. I suspect that something with my machine is flawed to this day...but I'll likely never know. The good news? I can't recall the last KP.

AHT is not very accurate.. but ASD is much better and I always recommend my clients to get ASD.. Originally reserved for Apple Techs only.. now you can get this powerful set of utilities not found on AHT...

Inquire by emailing me for more details.. You and your Mac Pro will be glad you did.

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Use ASD... Forget about AHT.. its not accurate at all.. ASD tells you whats wrong with your machine in simple english and not cryptic hex code.

macguy93 said:

Hello everyone,

I have been having issues with my computer from the day I bought it from apple (as I'm sure you've all seen from recent post) I finally got a hold of a VERY educated senior advisor at apple to help diagnose the problem. To make a long story short I sent him some system log files I had on some recent kernel panics and memory leakage problems I was having. I also sent him a .psx file of my system information and in that file he was able to diagnose I had one or more malfunctioning ram and something wrong with the Ethernet port on the logic board (I have no idea how this can relate to slow performance but some how it was interfering withing something...) anyway, he suggested bringing my computer into apple to have them run a thorough diagnostic test on the machine. They did several passes on the ram (14 or so) and everything passed with flying colors. He also ran test on the graphics card me hard drive too. Basically over the course of 5 days my computer did not show any signs of anything being wrong. So I got fed up of this and contacted another senior advisor and explained my issue. I told him how I went through every troubleshooting tip possible (including re-installing the OS 3 times) I was still having the same crappy overall performance. So he decided that he was going to schedule and on sight repair from apple and they are going to replace my entire logic board... Since that's all they can do at this point I figured why not..

So my overall question is, if there was something wrong with my computer could there still be a possibility that the test at apple couldn't have picked it up? Sorry for this issue being so broad, but I thought I would see your guys thoughts.

Thanks in advance!

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macguy93 said:

That makes me feel a little better to hear that!

issues as far as kernel panics (i assume, are when the computer will just restart in the middle of what your doing?) which have happened 3 times now and slow overall beach ball like performance be related to the logic board? (If its not related to software)

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Kernel Panics (KP) can look like a few different things:

• Sudden Restart (like you force quit everything suddenly and selected Restart)
• Complete Freeze up (nothing moves and you have to hold the power button in for 5 seconds to force a restart)
• The curtain of darkness (rolls down over your display and a text box appears in the center of your screen informing you to recycle the power in order to recover)
  
  On any or all of these you may be presented with a crash report either suddenly or after the restart.
  
  There may be others too - I forget.

The curtain of darkness (I just made up that name BTW) is probably the only one you can be certain is a righteous KP. The others may be a KP or could be loss of power to some sub-component, or could a total loss of sanity, or etc.
Beach balls can indeed be an indication of fault conditions or instabilities which may or may not lead to a KP. General system slowness can as well.

Any and all of the above may be caused by software conflicts, software generated exception errors, or hardware faults. Both software and hardware faults may be intermittent or reliably reproducible. And they can be any number or combination of things like power surges on your mains, failing memory in one or more components, failing MB components like regulators or cold-solder joints. Even a wire's, trace's, or MB component"s temperature in conjunction with any of the previously mentioned.

Diagnostic and testing software is good in that if it says "YOU HAVE BAD RAM" for example, then it's likely (but not certain) you have bad RAM and at the very least gives you a place to start the debug process. If further tests reinforce the AHT then certainty increases but if it doesn't then certainty decreases or another reason why should be tested. For example maybe the RAM is showing up as bad because a voltage regulator is bad or some logic on the riser boards are overheating or the MCH got partially fried in a previous overheating. And so on and so forth. With a bench full of test equipment troubles can usually be isolated much more exactly if the diagnostician is a good engineer but Apple won't do this and I dunno of any hardware vendors who will actually. They just replace components until the problem goes away in lite testing. If you come back to them more than whatever their tolerance limit is (2 or 3 times usually) then they try and sell you on the idea that the problem is environmental (noisy mains, phasing radio or micro waves, ground loops, and etc.) - which is a real possibility too.

i did by this computer factory refurbished from apple. the first day i received the machine i took a look inside and noticed there was worn out marks where the door snaps back in.. makes me wonder if the previous owner/where ever this machine was at had some work done to the inside numerous times to have that metal worn down.. A possibility to consider related to my issue..

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Refurbished is generally better than new because the non-faulty parts underwent an extensive burn-in and the faulty parts were replaced with new.

The worn out door should have been replaced. I'd mention that if I were you. But it doesn't necessarily signify the machine was serviced or repaired numerous times. That could imply any number of things. It's likely that the previous owner just reconfigured it kind of often and was rough with it when he did so. Impossible to tell.

PowerPCMacMan said:

AHT is not very accurate.. but ASD is much better and I always recommend my clients to get ASD.. Originally reserved for Apple Techs only.. now you can get this powerful set of utilities not found on AHT...

Inquire by emailing me for more details.. You and your Mac Pro will be glad you did.

----------

Use ASD... Forget about AHT.. its not accurate at all.. ASD tells you whats wrong with your machine in simple english and not cryptic hex code.

Click to expand...

How can I get ahold of the ASD??

also, is there some way to scan all files for our customers to see if they have any individual files that are corrupted? we get a few people with issues that completely go away once the OS is reinstalled, and then they get restarts and crashes once they move their files over.

is there a way to isolate them?

macguy93 said:

recent kernel panics and memory leakage problems I was having

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KPs and memory leakage don't necessarily mean bad hardware. Can we see the KP logs?

Jordanschultz01 said:

How can I get ahold of the ASD??

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Check the list to get the correct version number, and then google is your friend.

http://www.dannydullin.com/apple-service-diagnostic-asd-reference-list/