Very interesting and useful video. For some reason I have gotten the bug to do a little reminiscing and I purchased a couple of TI calculators on eBay/Mercari. I wish TI/HP/Casio/Sharp would make a modern “retro” LED calculator.
The cards without the black header are typically extra-use blanks that are not magnetic. The back side would be very shiny gray vs. the dullish dark gray/black of the magnetic cards. Typically, they were used for the TI-58C as it would remember your program when turned off. That way, you could write the labels on the card and slide it in for reference.
