SR-52A rebuild project (SR-52A 942058 LTA4176)

[albertofenini]

How to find a keyboard failure

If we short with a thin wire rows and columns at the pcb side the calculator works
and numbers are displayed and operations can be done

However, when the few working keys are pressed on the keyboard
the corresponding row and columns are not shortened together as we were expecting

As an example : the LRN key works and is obtained with column 4 and row 8
If we put an ohmmeter between this two points when we press the LRN key [/align]they don’t get shortened

I think we are missing how the keyboard works and this make difficult the repair

Any idea ?
Thanks for help !!![align=justify]