I don?t know if the internals at anything like the Classic 5, but I?ve just had a similar problem. In my case (no pun intended), the issue was a break in the ribbon cable from the membrane keypad to the main board. The cable is one complete piece with the switches underneath the rubbery bit, if that makes sense. It doesn?t lend itself to being repaired. To salvage the main function of mine (distance only), I?ve soldered leads into the ribbon cable socket (tiny) and just have two push to make switches to turn on and measure, respectively. You can work out the pinouts once you peel the rubber keys off. No idea if this is your issue, but putting it out for anyone else who needs the info. Saves buying an Aldi version for about ?20. 😂