Late 2015 iMac Black Screen with Chime but no #3 LED
I recently removed my iMac late 2015 i5 27” screen to upgrade the hard drive. (Something I’ve done successfully before). Upon re-assembly, the machine would not boot. Got a chime but then a full black screen.
I removed the screen again, checked all of the connections, and they seem good. I get LED #1+#2 lit up on the diagnostic, but no #3. I’ve read that this means the the video card and logic board are not communicating.
I’ve tried resetting the PRAM and the SMC with no luck.
- Are there any further suggestions about what to try to get it running again?
- Is there any value in pulling the whole thing apart to replace the PRAM battery? I read one place this could be a fix, but it seems like a lot of work if it’s a dead end.
Thanks for any help.
Is this a good question?