After installing new Hynix laptop memory (2X4GB PC3-8500 DDR3-1066MHz PC8500 204pin) in my Mac Mini 3.1 sometimes the fan got into high gear, sometimes it beeped multiple times, sometimes with a few second interval, but it wouldn't boot.
After reading the post below I tried one of the old 1GB modules in slot 0 (the one closest to the logic board) and a new 4GB module in slot 1. The Mac Mini booted and now I had 5GB of memory.
Then I put the 4GB back into slot 0 and pressed down with my finger on the module, and this would boot the machine as well. The old 1GB module had a tight fit in slot 0, the new 4GB module went in more smoothly. Perhaps the old one was slightly thicker pressing the pins of the connector down further.
After placing a 1cm wide piece of rubber on top of the memory module I could boot the machine with 8GB of memory installed. Picture 3 is an animated gif showing how far the module is being pushed down.
For instructions on opening the Mac Mini have a look at iFixit's teardown of the Mac mini Model A1283.
solforever Jan 29, 2012 11:44 AM
Re: Beeping sound after upgrading RAM on Mac Miniin response to steve359 I had the same problem as you on my mac mini. It was always slot 0 that had issues of need reading the memory. When i tried the old memory or just slot 1 then everything worked. Read on a thread it was how certain memory gets seated into slot 0 that causes it not to work. I went through 2 brands of memory both had similar problems when seated into slot 0. They both worked in slot 1 alone but nothing when in slot 0. What i did was what another thread advised to do. Take a small flat head screwdriver and after you put the memory in slot 0, put the screwdriver between the top of the mac mini and the memory then turn the screwdriver a little to exert pressure on the memory into the slot. Do it on both sides of the memory. I did this and tested out both sets of memory and now they both work. When i take out the memory and put it back in normally i get the beeps again. Do the same procedure with the screwdriver and they both work again. Its definitely a hardware issue and the seating of the memory in slot 0. Hope this helps cause it helped me tremendously after wanting to pull my hair out...