Hp-41C card reader - dead

[Vintage63]

Thanks to Teenix's couplers, which I can't thank enough, I have reassembled part of the card reader eager to give it a go. The motor works, the coupler and the worm gear work nicely when I give power to the motor.
I have launched 'Catalog 2' and I get the list of functions on the card reader.
If I call RDATA or VER it asks for CARD but if I insert the card nothing happens.
The first line I have when launching Catalog 2 is 'CARD RDR 1E' which casts some doubts on the integrity of the reader. Is this some kind of doomsday error?
Marco