Trying to recover 67's prerecorded magnetic cards

[aurelio]

I've found an article here about magnetic cards repairing, do you know alternative methods? i've tryed following those instructions, but I've difficulties in rebuilding with tape the missing corner.
What is the most common reason which makes these cards not readeable?

the attached pic shows the rear of a couple of these "sick" cards

[Thomas Okken]

Take a look at this thread, it mentions an approach that I have found useful: https://www.hpmuseum.org/forum/thread-14110.html

[Joe Horn]

I used to have complete success using the "Write-Protect Defeat Card" that somebody published in the Journal forever ago. To make the card, either cut it as shown or simply cut the whole lower corner off at a 45° angle, leaving the upper right corner as shown. Just push that corner lightly into the EXIT side of the card reader until its stops. This will make the card reader think that the card coming in from the other side is write enabled.



This trick only helps if the card being written to is magnetically functional. If its timing track is damaged, or if the data area drops bits, then you're out of luck.

EDIT: Oops, Thomas Okken posted while I was writing this. Oh well, here it is anyway.

[Dave Britten]

The bottom card in Joe's diagram is what I've used successfully on many HP 65 cards.

[aurelio]

(04-18-2020 07:27 PM)Thomas Okken Wrote:  Take a look at this thread, it mentions an approach that I have found useful: https://www.hpmuseum.org/forum/thread-14110.html

thank you Thomas, very much.....I will follow the cut 45° angle solution.
I'll worth to sacrificate a blank card for this purpose!
Important as you wrote, save it to another card first, I'll follow this your advice

[aurelio]

Thank- ou Joe, thank-you Dave

[aurelio]

Hi all, back again on this kind of issue.
I'm trying to rewrite the original card from a pack . I get "error" with different reader, different machines.
I used another identical prerecorded 100% working card and the "Write-Protect Defeat Card".
unsuccesful after several attempts, I mean that after a reading from the "good" card (program loaded on the 67 or 97, not manually loaded) I rewrote (I guess) the "damaged card", first side >>>>the other side>>>>0.00.
Then I reset the calculator trying to read the "newly written" card....no way>>>Error
I play the game smoothly with a fresh card, but not with the original ones...

I'm not sure if I'm doing well: the Crd and the 0.00 display after two passages sounds good, but the result is bad, does it means that the card is not rewritable at all, a defective media?

[teenix]

The 67 or 97 does not report a write error, except that if the sense chip data buffer has a problem, so you cannot tell if the data on the card is valid or not.

If it doesn't read from a few different calculators, that are known to read ok, then maybe there is a write problem. The only other practical way to test, is to write from different calculators if available and then read back.

Hmmmm this gives me an idea for the 67 and 97 CPU modules.....

cheers

Tony

[aurelio]

(08-16-2021 10:11 AM)teenix Wrote:  The 67 or 97 does not report a write error, except that if the sense chip data buffer has a problem, so you cannot tell if the data on the card is valid or not.

If it doesn't read from a few different calculators, that are known to read ok, then maybe there is a write problem. The only other practical way to test, is to write from different calculators if available and then read back.

Hmmmm this gives me an idea for the 67 and 97 CPU modules.....

cheers

Tony

Hi Tony, I've done the procedure using different calculators before to post; they all are supposed to write/read normally as I've checked, for this reason I thought the problem located in the card, maybe unrecoverable. I think it's definitively the original card: I tryed with a a rewritable "cut" card, this time it works, with all the machines.
How could be damaged the card from the original pack ? Apparently it has no external defects

[teenix]

(08-16-2021 01:26 PM)aurelio Wrote:  Hi Tony, I've done the procedure using different calculators before to post; they all are supposed to write/read normally as I've checked, for this reason I thought the problem located in the card, maybe unrecoverable. I think it's definitively the original card: I tryed with a a rewritable "cut" card, this time it works, with all the machines.
How could be damaged the card from the original pack ? Apparently it has no external defects

Maybe the magnetic strip has deteriorated over time and data can't be stored reliably anymore. I don't know if these can be refreshed by deguassing or not.

cheers

Tony

[aurelio]

(08-16-2021 05:18 PM)teenix Wrote:  Maybe the magnetic strip has deteriorated over time and data can't be stored reliably anymore. I don't know if these can be refreshed by deguassing or not.
cheers
Tony

I don't think so, if it works as for the HD I read that "a degaussed drive is inoperable in any system. The magnetic erasure rearranges the magnetic field to such an extent that standard read heads are unable to find a magnetic reference point for tracking.", so that "a degaussed disk cannot be used after degaussing".

[teenix]

Hi Aurelio,

Much like old tapes for general recording of music or voice, I don't think these have any sort of reference. The actual data on the card becomes the reference after it is written.

Probably already done, but have you tried cleaning them or using the eraser method?

cheers

Tony

[aurelio]

Hi Tony, yes, I've already tried with the "eraser method" using a white gum pencil eraser as explained by Sylvain, but unfortunately this didn't change the situation.
Thank-you
Aurelio

[Sylvain Cote]

Aurelio,
I have almost all the HP-65 & HP-67 application pac in my collection.
Several cards, about a dozen, are not working anymore and nothing can revive them.
Sylvain

[Dave Frederickson]

Degaussing is an excellent method of removing garbage data from magnetic media, like data from an out-of-alignment card reader or disc drive.

DO NOT degauss the hand-pulled cards for the 71B and 75 as these cards rely on a pre-recorded timing track. The timing track cannot be restored except by the custom machine HP used to originally write the card.

[BillBee]

Is there a way to use Tony's resources (67 Pacs) to rewrite the card's?

With his awesome board (of which I will order one in Oct) one should be able to transfer the program into memory via usb and write back through the reader. Mind you I am just thinking until I get the board to test.

BTW - Tony's work should be sucked down and immortalized on the flash drive. It truly is a marvelous resource.

-Bill

[aurelio]

(08-17-2021 12:59 PM)Sylvain Cote Wrote:  Aurelio,
I have almost all the HP-65 & HP-67 application pac in my collection.
Several cards, about a dozen, are not working anymore and nothing can revive them.
Sylvain

Thank-you Sylvain (sob....)
Aaaarg..... so the only way is to write onto a new card, entering manually each line of the program, step by step and using the original card merely as overlay for the A, B,C, D,E keyes

[teenix]

(08-17-2021 02:37 PM)BillBee Wrote:  Is there a way to use Tony's resources (67 Pacs) to rewrite the card's?

With his awesome board (of which I will order one in Oct) one should be able to transfer the program into memory via usb and write back through the reader. Mind you I am just thinking until I get the board to test.

BTW - Tony's work should be sucked down and immortalized on the flash drive. It truly is a marvelous resource.

-Bill

Yes, and if the entire PAC is in a single directory you can import the entire list of files in one hit - USB or Bluetooth.

You can then load each file and write the card(s).

I was thinking the other day that loading a file from disk and sending it to the calculator via Bluetooth which will then automatically write the card(s) saving a step. Also with a special card read mode, recall the raw card data to the PC to check out what part of the card is not writing or reading.

Future features, I got the Covid jab yesterday, feeling wishy washy so definitely not today :-)

I didn't realize that clearing a 67/97 program also cleared the calculator to default DSP FIX 2 and DEC modes, clears the flags and activates the default A-E functions. This could be a trap if someone was expecting the current non standard settings to be saved to a card.

cheers

Tony

[cahlucas]

Another thing to consider is (strong) magnetic fields. If a magnetic field, in the form of a permanent magnet, or an electrical device that creates a magnetic field, comes near the cards, all data on the cards can be disrupted or even erased. Therefore, it is best to keep the cards in a metal box, so that magnetic fields can no longer reach them. Add some moisture-absorbing granules in a cotton bag, so that the cards can no longer oxidize. I hope this will partly solve the problems with the cards. Sincerely, Karel.

[BillBee]

(08-17-2021 11:54 PM)teenix Wrote:  

(08-17-2021 02:37 PM)BillBee Wrote:  Is there a way to use Tony's resources (67 Pacs) to rewrite the card's?

With his awesome board (of which I will order one in Oct) one should be able to transfer the program into memory via usb and write back through the reader. Mind you I am just thinking until I get the board to test.

BTW - Tony's work should be sucked down and immortalized on the flash drive. It truly is a marvelous resource.

-Bill

Yes, and if the entire PAC is in a single directory you can import the entire list of files in one hit - USB or Bluetooth.

You can then load each file and write the card(s).

I was thinking the other day that loading a file from disk and sending it to the calculator via Bluetooth which will then automatically write the card(s) saving a step. Also with a special card read mode, recall the raw card data to the PC to check out what part of the card is not writing or reading.

Future features, I got the Covid jab yesterday, feeling wishy washy so definitely not today :-)

I didn't realize that clearing a 67/97 program also cleared the calculator to default DSP FIX 2 and DEC modes, clears the flags and activates the default A-E functions. This could be a trap if someone was expecting the current non standard settings to be saved to a card.

cheers

Tony

Fantastic Tony! If we could double the hours in your day I would start the petition for you to do a 41 board like that. <kidding>

I got the jab back in Feb and TBH the 2nd day was the worse. Not really bad but enough for a couple fingers of Scotch and a nap. Usually I recommend people get the shot on a Friday if possible. It gives the weekend to get back to normal.

-Bill