Oh. Em. Gee.
I owned this when I was 11. It upgraded my ZX81 RAM from 1K to a whopping 16K.
Then one day I plugged it in while the computer was turned on. Fried it. I was back to 1K. And that, my dear children, is how Daddy learned the meaning of heartbreak.
I still remember the details so vividly - the desk, the light, the room, the pain in my heart. Some things you never forget. https://toot.cafe/@moopet/114281679326051403