Ga door naar hoofdinhoud

Model A1311 / Mid 2010 / 3.06 & 3.2 GHz Core i3 or 3.6 GHz Core i5 Processor

342 Vragen Bekijk alle

Do I have a bad Logic Board?

Hi Everyone,


Backstory:

I was given a free iMac 21.5" (Mid-2010) from a friend, he picked it up from someone throwing it out and I have zero knowledge of this iMacs history before I received it. Most people would just scrap this for parts but since I'm currently typing this post on a MacBook Pro 15" (Mid-2009) in 2020, I thought what could I do with this thing.


What I've Done:

  • Turned it on, it had no start up chime, it beeped very loudly and the screen remained black.
  • I checked the RAM slot and it was empty. I installed some RAM I had removed from an old Mac mini.
  • Turned it on, I get start up chime, no beep anymore but the screen remained black.
  • I opened the iMac up and removed the LCD, I noticed a screw was missing, this has been opened before.

Block Image

  • First thing I noticed was the LCD wasn't connected at all. I also noticed the backlight connector and the v-sync connector were damaged (but pins were still good and is fixable).

Block Image

  • After removing the LCD, the second thing I noticed was the hard drive was missing (including the bracket), so I now assume the iMac stopped working, they opened it up, removed the hard drive, kept the RAM and tossed everything else.
  • I mounted a spare SSD using metal brackets I had, this works.

Block Image

  • I also noticed a metal clip was loose in the iMac, and I found it was meant to be mounted to the CPU heatsink, now I'm thinking the logic board has been removed or at least attempted to be removed).
  • With the iMac started up with or without the LCD screen attached, the logic boards diagnostic LED's only show LED #1 & #2. LED #3 & #4 remain off. Looking into this, I found the iMac 2011 GPU Upgrade thread and thought, well, seems all signs are pointing to the AMD GPU dying - being an old iMac in the 2009-2012 era, they just took the RAM and hard drive and were done with it.

Block Image

  • First I removed the "dead" AMD GPU and baked it in the oven for 10 minutes at 200°C. Plugged it back in, no 3rd LED.

Block Image

  • Ordered a NVIDIA Quadro K1100M GPU to replace the AMD card. Following the GPU Upgrade thread, it looked as simple as booting from the USB, SSH in, update VRAM on the GPU and we are back to a working iMac.

Block Image

  • I installed the K1100M into the iMac, noticing that the 3rd LED is still not lit (I read a post in the GPU Upgrade thread that said you won't get that LED until the card has been flashed so I wasn't too stressed at that point).
  • Made my bootable USB (tested it on my MacBook Pro - boots), plugged it in to the iMac, turned it on, I get the start up chime, fans run quietly, I look for the iMac on my network using a IP scanner - can't find it. After a little while the CPU fan runs at full speed and doesn't slow down at all. I still can't find the iMac on the network...
  • I notice there are no activity lights for the port going to my iMac on my network switch... No wonder I can't find it, it's not communicating.
  • I removed the GPU, cleaned the contacts with contact cleaner, reinstalled. Same issue.
  • I know the USB ports on the back of the iMac work because I was able to clear PRAM with a keyboard, so I connected a ethernet to USB dongle, this shows there is network activity at the network switch but I can't find the iMac on the network. I guess the dongle will communicate with the switch regardless if the iMac is involved or not...

So now I'm kind of stumped. Do I have a bad logic board? Seems I have no network at all? I was hopeful of this working because I was getting the start up chime but it seems it's stalling somewhere but I just can't see - This is all very hard to troubleshoot when I have no display.


I know I'm going to get the "give up", "buy a new iMac" reply, but this was just a "why not" situation, let's see if we can get this thing working. I already bought the GPU so I'm kind of invested.

Beantwoord deze vraag Dit probleem heb ik ook

Is dit een goede vraag?

Score 1
1 Opmerking

Did you get the 3rd LED on after flashing the GPU card? BTW, any updates?

Thanks for sharing your iMac fixing store!

door

Voeg een opmerking toe

1 Antwoord

Het nuttigste antwoord

The racing fan is caused by not having a hard drive with Apple’s proprietary heat sensor. This can be cured by using an OWC thermal sensor

https://eshop.macsales.com/item/OWC/DIDI...

Hook it up to an external monitor to see if it is generating a video signal. If that works go for the the LED driver board.

Was dit antwoord nuttig?

Score 1
Voeg een opmerking toe

Voeg je antwoord toe

Shaun Jay zal eeuwig dankbaar zijn.
Weergavestatistieken:

Afgelopen 24 uren: 0

Afgelopen 7 dagen: 0

Afgelopen 30 dagen: 1

Altijd: 82