HP48G Series Keyboard Hardware

[ijabbott]

There is probably no need to match the resistances exactly. After all, if the resistance comes from the traces themselves, it will vary depending on which keys are pressed on that row/column. If replacing with copper traces, it should be sufficient to add a discrete resistor to each row and column. These should be chosen so that the total resistance between a row and a column when a key is pressed is "typical". I guess the original resistances would have been chosen so that the memory would still work no matter how many keys were pressed.