Chosen Solution
I installed new memory & still get 3 beeps, have tried to reseat a few times, still same result. I did carefully vacuum inside, could I have damaged the logic board? The Mac was previously getting some lines on monitor Occasionally . Logic board was replaced 4 years ago. Thanks
It may be the case that one or both of the RAM slots have failed. If you haven’t already, you should try testing the system with only one RAM stick installed, first in one slot, then in the other. Then repeat with the other stick. If any of those configurations work, try to deduce whether or not you have a failed RAM slot, bad memory stick, or larger issue such as general logic board failure. Also it would be good to verify the style of beeps you are getting at startup. You can use this reference. There are two types of startup tones that give 3 beeps and it’s important to distinguish between them.
Well Sadly I suspect you killed your logic board with the vacuum! The rushing air through the hose can build-up a static charge so when you touched the nozzle to your system you could have zapped it! The rooms humidity will effect how charged the air is, so a very dry room (in the desert) will be a huge risk and if you where just in the shower so your mirror is fogged up your bathroom would have the least risk! If you want to get more out of this system I would strongly recommend installing a 2012 logic board. The 2011 boards have a weak GPU where the 2012 offers a much better GPU. The logic board is a direct drop-in with a slight modification to the LVDS cable as the Apple altered its supplier. A few strokes of a nail file solves that.
