Help me diagnose my 2009 iMac

[class77]

A month ago, my iMac woke up and was really slow to open some websites. I thought it was because the cache was full because I had been running 12+ tabs the night before, so I decided to restart the machine. I could never get past the grey startup screen after that. Took it to the Appple store and they wouldn't work on it because it was "obsolete". They ran the the short version of the hardware test and said something was wrong with the RAM. I replaced the RAM with RAM I knew was good and nothing happened, still couldn't get past the gray screen.

Took it to a local shop who would work on a machine this old. They determined that the hard drive had gotten corrupted. They wiped the drive, reinstalled from the backup and everything was back up and running. Worked great for about a week, then I started getting the spinning wheel of doom on a random basis. Sometimes, like now, I'm getting the wheel every 5 seconds for absolutely everything I do. Sometimes I go for days at a time and get none.

I have run the Apple Hardware Test and it finds nothing. I've verified the disk, I've verified and repaired permissions and SMART status says Verified. If it's a failing hard drive, I have no problem replacing it. If it's a logic board, I'm getting a new iMac. This machine ran flawlessly until a month ago and I'm at a loss on what to do or what to check.

Anybody have a clue what might be wrong or is there anything else I can check myself? I know just enough to be dangerous and don't know enough to actually troubleshoot it myself.

 

[stevefo]

Unfortunately its process of elimination, I would install OSX on an external HD/SSD and see if the problem goes away. If it does, its your Hard drive.

 

[class77]

Would a noticable lag in most streaming videos from YouTube(or other sources)be affected by a failing hard drive or a failing logic board?

 

[eRondeau]

I've got a dozen Mac's and I help my friends maintain perhaps two dozen more. I've seen numerous HD failures with symptoms that are identical to what you're describing. Meanwhile I've only seen a single "logic board failure"; it wouldn't even power-up at all. Your iMac is definitely worth fixing. Buy a SSD. You won't regret it.

 

[class77]

I've got a dozen Mac's and I help my friends maintain perhaps two dozen more. I've seen numerous HD failures with symptoms that are identical to what you're describing. Meanwhile I've only seen a single "logic board failure"; it wouldn't even power-up at all. Your iMac is definitely worth fixing. Buy a SSD. You won't regret it.

Did any of those hard drive failures show up on the Apple Hardware Test?? I've run both the long and the short versions and it shows nothing is wrong.

 

[eRondeau]

Did any of those hard drive failures show up on the Apple Hardware Test?? I've run both the long and the short versions and it shows nothing is wrong.

I never ran a Hardware Test. But you can often hear rapid but quiet clicking coming from the HDD as it fails; it's the actuator arm trying to read the sector repeatedly. The iMac's case will probably muffle it however. While you've got the iMac open be sure to vacuum all the accumulated dust/hair out (especially if you've got a pet) and ensure all the ribbon cables are tight into their connectors. I always remove & reseat all ribbon cables as a precaution. Note that even if you never use your optical drive, a bad connector to your optical drive can cause all sorts of weird issues -- slow boots between the power switch and the chime for example.

 

[class77]

I never ran a Hardware Test. But you can often hear rapid but quiet clicking coming from the HDD as it fails; it's the actuator arm trying to read the sector repeatedly. The iMac's case will probably muffle it however. While you've got the iMac open be sure to vacuum all the accumulated dust/hair out (especially if you've got a pet) and ensure all the ribbon cables are tight into their connectors. I always remove & reseat all ribbon cables as a precaution. Note that even if you never use your optical drive, a bad connector to your optical drive can cause all sorts of weird issues -- slow boots between the power switch and the chime for example.

My iMac is absolutely silent, except for the hardly detectable noise of the fans at 1200RPM. There is not and never has been any clicking noise from the hard drive. When the hard drive got corrupted and was wiped/reformatted, the case was opened/cleaned and the cables reseated. No noise was heard at that time either with the case opened.