HP-67 weird behavior after reading a card

[albertofenini]

Hi Tony, Hi everyone

we just tried,

first we changed the 1818-0231, but then when we powered on the calculator
the display was like -0000000000000 and the keyboard was stuck

then we changed the 1818-0232 and when we powered on the calculator
the display went back to 0.00

however, when we tried to key-in the test program the calculator behaved like before,
and even reading the SD-04 card was producing the same weird behavior than before the ICs swap

Any idea on what we can try ?

thanks again and take care !!!