Chosen Solution
I have upgraded the CPU on my iMac 2009. Now the screen stays blank after powering on, but the iMac is still accessible via Screen Sharing (vnc) and remote login (ssh). I can see that the new CPU is working as expected. I’m afraid that I broke the video connector to the LCD when I opened and lifted the LCD. Is it possible to test if the faulty part is the connector? I considered to test the video output via Thunderbolt, but I only have an old monitor with VGA input. Thanks in advance for any hint. Update (03/10/2022) Added some photos
Update (03/11/2022) I bought a cheap Thunderbolt to VGA adapter to test; when I login via Screen Sharing, the external monitor shows a copy of the main screen. So it looks like the fault is somewhere between the connector on the logic board and the LCD panel?
It looks like the connector was pulled away from the logic board as it looks like its at a bit of an angle and the grounding tabs look like they’ve been soldered down at this angle. At this point I think you’ll need to replace the connector, using solder wick clean off as much solder as you can from the contacts and then use a hot air station to heat up from one end lifting the connector legs making sure not to damage the pad below. As you unsolder the leg lift it up so it doesn’t resolder on. walk down the connector and then do the ends again being careful not to damage the pad under it. Clean off and tin the pads and mount the replacement connector LVDS Cable Connector (30-pin)
If you’re not able to solder on a new connector, you’ll need a new logic board. They can luckily be had quite cheaply on eBay.
