Several months ago I gave up on my Lenovo Thinkpad T420 because it would not boot. It was producing those dreaded boot up beep errors. Although the errors indicated the motherboard was the problem, I opened up my laptop and reset both RAM DIMMs.
Problem solved… for a month or so… or so I thought.
One day, I turned on my T420 and it gave me those dreaded beeps again. It didn’t matter what I did. The beeps sounded and my laptop wouldn’t boot up. I figured it had finally died, so I shoved it in a closet for the next few months.
On a whim, yesterday morning (Tuesday, June 26, 2018), I decided to give the T420 another look. I turned it on and it gave those same boot up beep error codes: 1 beep, 3 beeps, 3 beeps, 1 beep. I looked it up and after a bit of searching on the InterTubes, I came across two very helpful Web pages (refer to the references below). It turned out that the beep codes indicated that the problem was a RAM issue. At least that was something than can be remedied.
I proceeded to check the RAM. I took out the one DIMM that is right under the small access panel and rebooted. Nope, that wasn’t the one. It figures it has to be the RAM that is under the keyboard. Murphy’s Law gets me every time. As far as I’m concerned, putting one RAM socket on the bottom and one under the keyboard is just a bizarre way of doing things. It was probably easier for manufacture, or just a bad design.
I took out the RAM that resides under the keyboard and replaced it with the other stick of RAM, and started the T420 up again. Booted up with no errors. WooHoo!!! I put everything back together and even replaced the spinning hard drive with a 480GB SSD (Sandisk Ultra II) that I had sitting in my desk drawer waiting to be used somewhere.
Okay, now I have a working T420 with Ubuntu Mate 18.04 on it. It runs like a dream, except I went from having 16 GB RAM to 8 GB RAM, then I remembered that I had two 4GB sticks of DDR3 RAM sitting in the desk drawer that had come out of my old mid-2010 MacBook Pro when I had updated it from 8 to 16 GB RAM a number of years prior. I put in one of the 4 GB DIMMS and now I’m up to 12 GB of RAM. I can live with that until the 8 GB RAM comes back down in price a bit.
Now, my T420 is a happy laptop working perfectly. After not using it for several months, I did forget how enjoyable it is to use.
Happy computing all!!!
Beep and No Beep Symptoms – Thinkpad General: https://support.lenovo.com/us/en/solutions/ht035729
Thinkpad.com Support Community: https://forum.thinkpads.com/viewtopic.php?t=11195