HP-67 Diagnostic cards, different versions different behavior

[albertofenini]

Hi everyone,

when testing read and write capabilities for the HP-67 we usually take Lunar Landing or Days Between dates as test cards.
We read them, we try to copy them, usual things

Don't know why, yesterday we run the diagnostic card (as it should be done by good technical people )

We have one version SD15A that behave as described in the Standard Pac Manual,
but we also have found a couple of Diagnostic Card SD15C (possibly a later revision)
that behave differently

The SD15C is a two sides card like the SD15A, but after having read it and pressed the A key to start the test
it pause almost immediately showing a 57 and then it goes on almost forever (*) without showing
anything interesting

(*) we have stopped the execution after more then three minutes

BTW:
The unit is working fine and the SD15A returned positive results
Two different SD15C on this same unit has shown the same described behavior

Does anyone has ever experienced this before ?

Thanks everyone !

If someone is interested in the pictures, have a look here : HP-67 1612A01116