I have a bad memory slot
I'm working on a MacBook Pro 13" 2.4GHz (Mid-2010) that has a beep every 5 seconds. After a bit of troubleshooting I found that the top memory slot is bad. The MacBook works fine with each 2GB memory module (installed one at a time) in the bottom slot. Anything installed in the top slot causes the beeping error. I have tried cleaning the pins of the slot with Isopropyl Alcohol and compressed air. Instead of replacing the Mother Board, I thought why not just run it with memory only in the bottom memory slot and instead of only 2GB, put in a 4GB module. It won't boot with the 4GB module installed. It hangs on the spinning sprocket. Normally, nobody would run a MacBook on a 0+4 configuration, but has anybody tried? I either have a bad memory stick or it's not possible. It runs fine in a 0+2 configuration.