iMac 2017 don't turn on after switching faulty HD to SSD
Some years ago I bought this iMac 2017 21.5” from second-hand. From day one it was super slow and almost unusable. After trial and error I figured it was a problem with its HD. I connected a SSD via USB to SATA to it, set it as the startup disk and it worked fine – except for the fact that it turned off frequently by itself and restarted. From time to time the startup disk preference was forgotten and it booted to its original HD, but I was able to revert startup back to SSD. At some point last year though after that happened I was never able to revert my startup disk to my SSD. It seems that it booted on its original HD and finally the faulty HD gave up and got corrupted. I wasn't able anymore to load macOS from its original HD and set my startup disk to my external SSD. I couldn't do anything besides opening it, remove the HD and switch to the SSD, which took me very long to do. I did that today and after replugging the monitor and plugging it to power, it wasn't turning on. I'm seeing only two LEDs after pressing the power button and the fan is turning on. According to this "Diagnostic LEDs" post it means that
- "If LEDs 1 and 2 are on and LED 3 is off, then the backup battery (on the back of the logic board) may need to be reseated or the logic board may need replacement".
- I also read that "Logic board diagnostic LEDs will not progress past LED 2 with a bad CPU".
- And lastly "LED 3 Indicates that computer and video card are communicating. This LED will be ON when computer is communicating properly with video card. If LEDs 1 and 2 are ON and you heard the startup sound, but LED 3 is OFF, then video card might be installed incorrectly or need replacement", however I'm not hearing the startup sound at all
I would like to try to figure out what might the issue. I've tried to turn it on with the SSD, went back with its faulty HD and with no HD / SSD. I'm always getting only LEDs 1 and 2 on. I never had any visual issues with its GPU (vertical or horizontal lines etc), but I was never really able to tell what was causing it to reboot itself since I started using it.
I'd greatly appreciate any help or suggestions on this. Thanks in advance!
Update (05/09/23)
@danj Hi, Dan! I just changed the iMac's battery but no dice. I still get LED 1 and 2 on, the fan spins, and nothing else. I tried with the display unplugged and plugged in. No chime sound. Is there anything else I could try? Does it make sense to try to connect to another monitor via USB c to HDMI? (In case I damaged the display connectors)
@danj I also considered doing a GPU reflow process, but since the GPU is integrated to the logic board in this iMac model, that doesn't make sense, right?
Video of the diagnostic LED: https://youtu.be/e8ju3IQdSN8
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5 commentaires
@thiagocapanema - Well that sucks ☹️
Let’s give this a try first disconnect the drive fully, see if that changes things. Then try connecting a external Monitor via HDMI.
I just can’t see how you killed your system.You did follow the iFixit guide to the letter and used the pizza cutter tool to cut the adhesive? If not you may have dated something that way.
par Dan
@danj For the SSD upgrade and for the battery replacement I followed OWC guides on YouTube. I have all the tools available on iFixit iMac SSD Upgrade Kit. I used the pizza cutter to cut the display's adhesive. I didn't find that much difficult to change the battery and reassemble the iMac.
par Thiago Capanema
@danj What should I expect after turning it on without a HD? I just did that. One thing that changed after I replaced the battery is that after putting the plug in the outlet the two LEDs turns green and the fan starts spinning. If I hold the power button for 5s LED #2 turns off, then turns on again. If I hold power button for 10s only LED #1 is green
I reconnected the original HD to it and after turning the computer on the HD also turns on and starts spinning. I wanted to check if the HD was turning on since I can hear it as opposed to the SSD. I don't know if that means anything though
par Thiago Capanema
@thiagocapanema - Did you alter the RAM? See if reseating it solves this.
With a new drive it sometimes takes a bit of time for the firmware to realize there is no OS to boot from, even still you should see the icon on the screen.
par Dan
Since I have nothing to lose, today I'll try to reflow the GPU using this method: https://www.youtube.com/watch?v=NFIgZpHJ...
par Thiago Capanema