I have an iMac with a cracked screen. The screen is lm270wq1 (SD)(F2). Same story, I see a number of replacement screens of nearly the same model with just the F2 changed. I understand much of it is just a plug change and that's simple enough to change. I'm just having trouble finding which of the many variants will work. I've found several for around $100. I don't want to pay any more for such an old Mac. Can anyone tell me which models are compatible?