Recommend me a good forum for iMac issues?

Does anyone know of a good, helpful, forum to get help and advice about an old iMac that is playing up?

I know there are the official Apple forums, but from years back I found the peeps there are more annoying than helpful!

In case there are any experts here…

Mid 2010 27in iMac running High Sierra.

Internals are mostly as standard, expect I removed the optical and replaced with with a ssd. I did this years ago, and everything worked fine. Until now.

The machine itself hasn’t been used for some time, although it has been switched on and woken up from time to time. I was just getting it ready to give a friend, and that’s where the issues started.

Initially I added the friend was added as a new user and I removed my user account. The issue is that sometimes it won’t wake from sleep, instead going to a black screen with a white line alone the top. if you let it sleep again it normally wakes up fine. Although sometimes, when away, the screen just goes white. Again, letting it sleep and woken seems to fix things. Sometimes you have to reboot.

I figured it was best to just wipe and re-install the OS, so did that but the issue still persists. I thiouth maybe it was the ssd I added causing the issues, so installed the OS on the old HDD, same issue.

At this point you’d nornally be saying “do an SMC reset”. And this is there it get’s interesting. I can’t! The reason I cna’t is that as soon as it’s plugged in, it boots. It doesn’t wait for the power button to be pushed. And this is with the “wake after power failure” option off.

Anyone any ideas, or know of a good forum to try for advice?


If it starts up without using the power button, then it is very likely to be a PSU issue which would be consistent with it restarting.

If you have spares to try and enjoy burrowing inside a 27" iMac then try them.

The PSU and Graphics card are top of the list of suspects on iMacs.

Those would be my instict too, but what throws me is that it took for the OS to be changed a lot (in terms of removing an old user and/or re-installing the OS) for the issue to appear, so I’m wondering if it’s software related? Or, can a software change trigger a weakness the in the hardware?

Put it back to a known working OS to elimanate this as a cause of the issue. I think it is unlikely though.

Working 12 year old 27" iMacs are becomming rare.

I had the same start-up problem with a 2010 iMac 27 and found it to be a known issue for that year. It was the graphics “card” that had failed.

This is not a removable card but a pcb hardwired into the logic board and I had a Mac specialist solder in a new one - a very fiddly job and no guarantee that it would work. And sadly, it didn’t… the problem went away but I was left with a completely blank screen.

Not the best news I’m afraid but it may save you the inevitable dead horse flogging.

It’s just gone black when rtrying to close a window, so I’s say that is defo the graphics card. Shame for my friend, as he was looking forward to getting another couple of years out of it, but to the big Mac graveyard it goes.

Although, saying that, I wonder what a new logicboard costs now? Can’t be much as not exactly a lot of demands for them nowadays!

Might have a look on Fleabay.

Have you tried a hardware test?