Multiple MagSafe Board Failures

Hi all.

I have a MacBook Pro 15" Unibody mid-2012. I have two 85w power supplies that I use interchangeably. One stays at my desk at home and the other travels with me.

While using the 'travel' charger the other day, I heard a pop (I think from the charger/brick) and the charging indicator light wouldn't light up. The MacBook showed it was running from battery. I unplugged it immediately but was in the middle of something important continued working since I showed I had 95%-ish battery remaining. At around 45% I had completed my tasks and went to plug it in using the 'desk' charger. The charge light wouldn't light up and the on-screen indicator showed that it was running only from battery. The desk charger still works on an older MacBook Pro I have, so I can see that the charger works fine.

After some diagnosis I believed the MagSafe board had gone bad. I bought one from Amazon and installed it.

It worked! At this point my Mac's battery was at 1%, so I left it closed in sleep mode and charged it until the charge indicator on the power supply went green. I left it closed and didn't touch it. About 30 minutes later, I heard it restart on it's own. At this point, the light on the cable wasn't on anymore. It was still plugged in. I opened it and let it boot with the charger still attached. It showed it was running from battery only and wasn't charging. I used it long enough to run a backup and I'm down around 40% before shutting it down.

All signs seem to point to a bad MagSafe board again. The desk charger still works with other MacBooks. I've ordered a second replacement MagSafe board that will be here in a few days. I'm concerned that the problem will present itself again. What else should I be looking into? Battery? Logic board? Gremlins?

Thanks for your replies! I'll do my best to post updates and answer any questions.