I thought readers might enjoy seeing this process, and the documentation may be useful to some as well.
The white line on the right housing for the ribbon is near the top, indicating that the ribbon is almost used up.
When you pull the housing cover open, you can see that the indicator is actually in the red zone (which was hidden in the shadows in the photo above).
On the left side, the take-up reel is getting very full.
The Executive waits for a fresh ribbon with open arms.
I happen to have a pack of a dozen IBM Electric ribbons which I picked up on eBay a few years ago. To judge from the markings on the cardboard box, these were produced for the military in the 1980s.
Let's remove the used ribbon.
The ribbon passes between two rollers that can be held apart using the switch I'm pointing to.
The ribbon pulls off.
This is not a private means of communication. The typing is clearly visible. Some business documents were typed on this ribbon in 1984. I bought the machine last month, and I've been using it for letters, brainstorms, typecasts, comments on student papers, and more.
I insert the new ribbon through the ribbon vibrator and guides.
Then it goes onto the shaft in the right-hand housing. This is a little tricky because the ribbon is slippery and wants to get tangled if you're not careful. Note that the indicator is now down at the bottom. On the far side of the ribbon, not visible in this photo, is the other end of the indicator piece, which is pushed out by the fresh ribbon, causing the indicator to move down.
I thread the ribbon between the rollers and onto the take-up spool.
And we're back in business. Now you just close the left and right covers, and you're ready to type.