The Big Bear Precipitation

At the cabin, as always, Sheldon is sitting in his traditional spot: on the right seat of a couch that sits in the middle of the room.

Amy asks Sheldon if he's ever been off the grid and he replies "once, the battery ran out on my phone, I had to wait for my iPad to turn on". However, in The Space Probe Disintegration (2015) he has no signal on his phone when in the shopping mall.

CHUCK LORRE PRODUCTIONS, #525

It's time for me to come clean. I'm the guy who helped the FBI hack the iPhone. Why did I do it? I don't know, why do people climb mountains? The standard answer is, because they're there (although I've long believed that mountain climbers have loveless marriages that force them out of the house and into a Sherpa). How did I hack the iPhone? To be completely honest, like many gamechanging breakthroughs, it was an accident. I was actually fooling around in the kitchen, trying to make a meatloaf sandwich without using my hands. Why am I coming out with this story now? Well, that's a tougher question. The truth is, I didn't want to, but my lawyers encouraged me to get ahead of the lurid tabloid stories that will be coming out shortly (my hands were not "otherwise engaged"). To set the record straight, my motive for assisting the FBI was simple patriotism. I never had any desire to profit from my discovery. Ever the altruist, I will use the fruit of my hightech chicanery to help the wives of mountaineers break into their husbands' iPhones while they recover from "altitude sickness."

References Alvin & the Chipmunks (1983)