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Full Version: Bypassing write protection in HP-67/97 Cards
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Hi all,
I was wondering if there is any software command or any trick I can use to re-write the cards from an HP-67 that have been write protected (the corners of the card have been removed).

Thank you all :)

Connect together the signals for leading edge of the card and write-protect. These are test terminals (F) and (H) on the top side of the card reader circuit board. A jumper between these points defeats write-protect.

This also works for the 67, points HDS/ and WPS on this diagram: Tony Duell's 67 Internals

Quote:
I was wondering if there is any software command or any trick I can use to re-write the cards from an HP-67 that have been write protected (the corners of the card have been removed).

Way back in early 1975 in the 65 Notes (precursor to the PPC Journal) issue V2N1 page 2 was a paragraph by David Kemper titled "Correction Card" in the monthly TIPS column. It described how to cut a mag card with an end sticking out which exactly matches the cut corner on the write-protected card. You would place this one into the exit slot of the card reader; then with the calc in "W/PRGM" mode, insert the protected card into the reader as normal and the card will be recorded as normal. A clear picture/diagram of how to cut the card is shown two issues later in V2N3 at the bottom of page 1.

I believe this technique works for both the HP65 and 67. If you can't get to the link, feel free to email me at jakes <at> pahhc <dot> org.

Jake Schwartz