Wrigley Field historical sleuthing: 1970s Jack Brickhouse edition

Last week, I ran this photo of a young Jack Brickhouse in the Wrigley Field broadcast booth and sleuthed out the date, which turned out to be September 3, 1949.

The photo above is of an obviously older Brickhouse, again in the Wrigley WGN-TV broadcast booth, somewhat excitedly holding a modern calculator. (Well, “modern” for that time, anyway.)

Can I sleuth out the date here? Well, of course I can, otherwise you wouldn’t be reading this!

Before I get to that, I thought that perhaps the calculator might help find the date. I found the calculator — it’s a Casio 805-MR — but that didn’t help, as that calculator was manufactured beginning in 1976. That does narrow down the time frame to 1976-81 —…