HP-71b Card reader "WRN: R/W Error"

[Nenad (Croatia)]

Hallo everybody (after a long time)

Please, help me to make my HP-71b working. I have bought it from the very respectful member of HP calculators community rather long ago, so I do not have any reason to doubt whether it is operational or no. Here is what I have done, step by step:

1) Typed the following program:
10 LBL EQ2
20 INPUT A
30 INPUT B
40 C=A+B
50 PRINT C
60 END

2) Cleaned an empty card by means of an isopropyl alcohol small tissue and let it dry completely

3) Entered the command
COPY EQ2 TO CARD

3) The machine responded:
Wrt: Align then ENDLINE

4) Inserted the card into slot, aligned properly

5) Pressed END LINE. The machine responded: Pull 1 of 1
I pulled the card through the slot completely out
(there is a YouTube video about this, so I do not have any doubts)

6) After several seconds the machine responds: "WRN: R/W Error"

After having done this several times the response is always the same. Tried to pull the red abrasive card three to for times through the reader: no change.

I also tried the step (3) with the reader removed. The machine responded with something as "No card reader". IMHO, this is important, because the 71b obviously recognizes the reader itself.

a) What should I try next to make my card reader work.
b) Somebody somewhere mentioned "degaussing" of the reader. How to do this?