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?

[Joe Horn]

(11-10-2018 09:23 PM)Nenad (Croatia) Wrote:  a) What should I try next to make my card reader work.

IIRC, if the timing track on a card gets messed up, the card will never work correctly, so the problem MIGHT be that particular card. So I'd suggest trying as many other cards as you can get your hands on. If NONE of them work, then the problem probably lies elsewhere.

[Nenad (Croatia)]

Unfortunately, I have a set of 5 cards+abrasive red card available and have tried them all. They are intact-AFAIK they have not been used before in other card readers. The result remains the same.

Can I somehow "format" them?

(11-11-2018 04:00 AM)Joe Horn Wrote:  IIRC, if the timing track on a card gets messed up, the card will never work correctly, so the problem MIGHT be that particular card. So I'd suggest trying as many other cards as you can get your hands on. If NONE of them work, then the problem probably lies elsewhere.

[Dave Frederickson]

(11-11-2018 09:04 AM)Nenad (Croatia) Wrote:  Can I somehow "format" them?

No. The timing track on the cards was written by a special machine at HP. See the HP Journal issue for the HP-75 which uses the same card reader, June '83, p. 20.

[Nenad (Croatia)]

Thank you for the text you pointed to. The most important sentence from the text in my case is: "Since even blank cards must have timing tracks and data tracks, every card sold must first go through this recorder..." So, may new cards may also be defective.

So, I have on my disposal the HP-71b, its card reader, a set of 5 cards and one red abrasive card. I tried each and every of the cards (both left/right sides: the one with HP logo and the one without), obtaining always the same result: "WRN: R/W Error"

What should I do next to find out whether the problem lies in the card reader or in the cards?

Thanks in advance.

(11-11-2018 09:42 PM)Dave Frederickson Wrote:  No. The timing track on the cards was written by a special machine at HP. See the HP Journal issue for the HP-75 which uses the same card reader, June '83, p. 20.

[Dave Frederickson]

(11-12-2018 12:36 PM)Nenad (Croatia) Wrote:  What should I do next to find out whether the problem lies in the card reader or in the cards?

It looks like the card reader is bad. It should be tested in a known good 71 with a known good card.

Also, in line 10, LBL is not a valid statement. Use the NAME command, [f]C, to name the workfile to LBL, and see if that had something to do with it.

Dave

[Nenad (Croatia)]

Thanks for your advice. Ok, I have corrected the program:

PURGE
EDIT EQ2

10 INPUT "A"; A
20 INPUT "B="; B
30 C=A+B
40 PRINT "A+B="; C
50 END

and then tried:
COPY EQ2 TO CARD

The response is again "WRN: R/W Error"

Unfortunately, I do not know anyone here in Split, who has even a HP-71b, especially with the working reader or working cards.

[Nenad (Croatia)]

Thanks for your advice. Ok, I have corrected the program:

EDIT EQ2
10 INPUT "A"; A
20 INPUT "B="; B
30 C=A+B
40 PRINT "A+B="; C
50 END

and then tried:
COPY EQ2 TO CARD

The response is again "WRN: R/W Error"

Unfortunately, I do not know anyone here in Split, who has even a HP-71b, especially with the working reader or working cards.

[Roland57]

(11-22-2018 09:20 PM)Nenad (Croatia) Wrote:  ...
Unfortunately, I do not know anyone here in Split, who has even a HP-71b, especially with the working reader or working cards.

Hi Nenad,

pls. send me a PM with your address and I'll send you 2 or 3 blank working cards for your 71B

Roland