iMac Pro 2008 iMac doesn't boot

[zNdjenja]

I have been gifted an old iMac but it seems stuck on boot screen, Have tried to hold option+R, holding shift button but nothing, im trying to boot it form a usb but it doesn't show up when i hold option. Any ideas?(also the screen a bit glitchy)

 

[DeltaMac]

The graphics corruption could be just a graphics card, or problems with the logic board, or could be (less likely) just a problem with RAM (or a combination of those) If you really want to resurrect this old iMac, you could start with replacing the RAM, check for any change in booting, then try replacing the battery (a button battery on the front of the logic board. After that, it gets quite time-consuming (really time wasting at this point). Parts (actual working parts) are getting more difficult to find. Easiest way is to find another like Mac model (working or not), and start swapping parts to see if you get anything working. Done this a few times (it's a hobby), and have a 20-inch, early 2008, fully working, running Sonoma/OCLP, getting ready to update to Sequoia when that is released next week. Some will say working on a Mac that is approaching 20 years old is never worth doing. I choose to disagree.

 

[zNdjenja]

The graphics corruption could be just a graphics card, or problems with the logic board, or could be (less likely) just a problem with RAM (or a combination of those) If you really want to resurrect this old iMac, you could start with replacing the RAM, check for any change in booting, then try replacing the battery (a button battery on the front of the logic board. After that, it gets quite time-consuming (really time wasting at this point). Parts (actual working parts) are getting more difficult to find. Easiest way is to find another like Mac model (working or not), and start swapping parts to see if you get anything working. Done this a few times (it's a hobby), and have a 20-inch, early 2008, fully working, running Sonoma/OCLP, getting ready to update to Sequoia when that is released next week. Some will say working on a Mac that is approaching 20 years old is never worth doing. I choose to disagree.

Thank you for the reply, i don't really have the time to work on it, have been trying to fix it without changing parts but seems impossible, it doesn't want to boot from a usb either, this is my first time getting my hands on an iMac and i like the design even if its old but such a hassle to work on.

 

[Adora]

Thank you for the reply, i don't really have the time to work on it, have been trying to fix it without changing parts but seems impossible, it doesn't want to boot from a usb either, this is my first time getting my hands on an iMac and i like the design even if its old but such a hassle to work on.

Already tried NVRAM/PRAM and SMC reset?

 

[zNdjenja]

Already tried NVRAM/PRAM and SMC reset?

How do i do these? i have tried also command+V but it reboots and freezes again

 

[Adora]

How do i do these? i have tried also command+V but it reboots and freezes again

​

Just leave out step 1 and try this. Fans should get loud if it worked. You have to turn it off again for the fans running normal.

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Reset SMC On Mac Mini, iMac, iMac Pro Without T2 Chip​

Follow the steps below to Reset SMC on desktop versions of Macs like iMac, Mac Mini and Mac Pro.

1. Click on Apple Logo > Shut Down and wait for your Mac to shut down.

2. Unplug the power cord from your Mac.

3. After 15 seconds > plug the Power Cord back in.

4. Wait for 5 seconds and press on the Power button to restart your Mac.


The other reset would be holding (alt)option+cmd+p+r directly after turning it on until it reboots again.


You can also do a hardware diagnostics by holding D directly after turning it on and release the key when you see a progress bar.

 

[Adora]

Also there are mostly a lest two RAM modulkes in iMacs and you could can test it with both of them only, if one is damaged.

Seems those came mostly with 2 x 1GB and can be upraded to 2 x 2GB. But it could also support more. Apple is always lying there, at least for the Macs since 2010 it was always double the amount possible.

But I am not sure for those older ones.

Install memory in an iMac - Apple Support

Get memory specifications and learn how to install memory in iMac computers.

support.apple.com

Maximum RAM is 6GB. Didn't even now 3GB modules existed. The cheapest one came with only 1GB (maybe 2 x 512MB), if it's one of those:

https://everymac.com/ultimate-mac-c...ntel015&prod2=iMacIntel016&prod3=iMacIntel018

The slower 24" is left out, because I can only compare three at once and don't know what size you have.

The PDF is from MacTracker.