HP-65 more on the card reader

[albertofenini]

Hi everyone,
we changed all of the three capacitors, but nothing changed.
Reading works like a chime, while writing doesn't work at all (WA and WB traces are attached).
As said, we changed, or swapped EVERY possible item from other working units.
The only thing we couldn't change was the keyboard.
What chances there are that the fault is in the keyboard component ?
Thanks to everyone for the effort in helping us !