2011 iMac 21.5" 2.7Ghz Doesn't See RAM - Beeps

[whitetw533]

So I was gifted a 2011 iMac 21.5" 2.7Ghz and ordered new RAM for it. In the meantime, the spinny hard drive quit so I also ordered an SSD and install kit w/ OWC sensor adapter. Did the HD and the RAM at the same time. All gear advertised to work with Mac, commenters verified function with the same model.

I now get the continuous beeps every 5 seconds and blank screen; it thinks there's no RAM from what I've read (I even timed the beeps).

Blew out the slots with compressed air, slot pins look straight and undamaged, verified proper seatment of the RAM modules (I think). They all went in with a pronounced detent and are not loose.

Tried all the permutations of modules and slots, no luck.

Maybe the RAM I got is wrong; put the factory set back- still beeps.

Im having trouble thinking that all four slots went bad at the same time and/or both the factory ram modules simultaneously quit.

At a loss for ideas, all of the posts I find end up being solved with the factory ram reinstalled.

Is there something I'm missing here? Is there something I could have unhooked or damaged when I took the display out to get at the hard drive?

If done countless memory upgrades on a variety of machines (including iMacs) without issue. Also have done hard drive replacements on other iMacs including a 2011 without issue.

 

[Calibre5]

I had this on a late 2012 27" iMac after replacing a failed stand hinge.

Turns out it was caused by the CPU heatsink moving a fraction due to slightly loose fixing screws. I must have knocked it during disassembly/re-assembly. On this model Apple don't use a CPU clamp and as the thermal paste "glues" the CPU to the heatsink they both move.

The fix was to strip the iMac down again and carefully re-position the CPU. Took about 4 attempts before I got it in the right place but no serious harm done and I'm writing this on the iMac 2 years later.

Good luck.