Text on HP 67/97's



I have just received my first HP-67. It has a home made card in the standard pack labled "trick". When you press A the screen flashes, blanks briefly and displays this,

I see all
I do all
67 is good
67 is god
all obey
or else.

I don't think the HP-67 is capable of displaying text. Side 1 of the card contains a program, side 2 contains data. The program seems to display the text which is stored in the registers. Have I stumbled on some undocumented feature? Does anyone else know about this???


I would suggest reading both cards in an HP41 Card Reader and try to figure out their contents. I was once told that both 67 and 97 allow some sort of synthetic programming, too. Maybe just rumor... I don't know.

If you find something else, share with us.

Good luck.


Officially an HP67 can't display text, of course. But I've heard that non-standard numbers (non-normalised numbers, ones with nybbles containing values>9, and so on) can produce some 'interesting' displays.
Maybe that's what you've got there. I am also told that non-normalised numbers can cause an HP97 to burn out its printhead, so take care if you are playing about with that machine...


Does it mean characters different of those printed when listing programs? The programs in the HP97 are listed in a alphanumeric way, isn't it? Is there another character set than this one?

I realy don't know.


Those 'text' displays are generated by recalling Non-Normalized-Numbers from registers. They were generated in the gold days of early synthetic programming by toying with the power source. Very low levels would sometimes
generate NNNs, as well as any of the 6 synthetic 67 instructions (including an amusing LBL (i) ! :-)

By the way, NEVER, NEVER, NEVER try to print those Non-Normalized-Numbers on an HP-97. You're very likely to burn its printhead before you realize what's happening. I know from experience since I did it once, and was only
aware of the printhead destruction when I smell some smoke
in the air ! :-( I've always regretted it !


Really? How does this fellow have them coded on a card?


At the very moment they are in memory (say, stored in registers), I think it is easy to record registers contents as in the 41´s Card Reader. Despite what they have stored, their contents, even being NNN´s, can be recorded on magnetic cards. Agree?


I tried to find any information about the 6 synthetic 67 instructions mentioned in the previous post, but I could not locate anything in the museum. Would anybody give some more info about them and how to obtain them on a HP67.


That's the point. I know 41's program cards cannot be read by the 67/97, as status and WALL cards (they are meaningless for both 67/97), but what about data cards?

By using some synthetic technics, these NNN can be generated in an HP41 and recorded in a magnetic card so they can be loaded in an HP67. If, and only if, a data card written in a 41 can be read by a 67/97.

Just wondering, as I do not have an 67/97 for testing.


I tried to track the program creator down, the seller says he is the original owner and recieved as a gift. I lost track there. I did learn this, The data appears to be modified numerals (lika 8 with the end cut off to make an E), displayed by placing the numbers in the stack and using the review stack instruction. I own a HP-67, on a HP-97 it would probably print the register data and ruin the printer. When I attempted to add to the storage register the result turned out to be an unrelated number. If you wish I can include a picture in a seperate post. I have alsoheard the "flash" screen can make strange numerals.
I don't think the HP-67 is able to read HP-41 software or data. I can't test this though as I only have a HP-67. The screen seems to blank for about 20 seconds before displaying the measages.

This is all I Know.



I suggested the HP41 would read the 67/97 cards, not the opposite; the HP67 cannot read 41-generated cards. Anyway, after all explanations given, the hardest part is already done: collecting those NNN rarities and storing them. If the cards are read by the 41´s Card Reader, the registers would be filled with some stuff that would be understood as anything but numbers. Maybe when they are recalled to the X-register, they would read like an ALPHA string, with some unreadable characters. Just a hunch.

After all, some new information (at least for me).

Good luck and thank you all.


Hi all,

some days ago I discovered by chance an article from Wlodek Mier-Jedrzejowicz (a name you can find really often in connection with HP-calculators) on this website:


It´s about HP calculator history; in the last 3rd of his article about the HP-67 he decribes "non standard instructions".
They are generated by interrupting the power supply in order to corrupt the RAM.

I tried to do it also by moving the battery pack a bit but without success up to now (don´t know if there must be already a program in memory or in which position the W/PRGM-RUN-switch should be).
Up to now I had no time to build up a device similar to the mentioned "phase boxes".

All in all not much news in addition to the responses above
but more a confirmation.

Maybe we are able sometime to share the experience of our HP-67´s ancestors.



Hello Robert,

I own a HP-67 since not very long. After reading your message and the article from Wlodek Mier-Jedrzejowicz I have tried moving the battery of my 67. Since the battery pack I have is 100% hand made it hasn't been difficult to short-circuit the calculator momentarily. I couldn't produce strange program instructions but after several atempts I've been able to produce these NNN numbers:




(the underline ___ means only blank display, not a dash)

the intersting thing is that I've been able to produce this second number twice so it could mean that their production could possibly be controled (with the apropiate technique --phase boxes, etc.)

I could store them in registers as if they where normal numbers, but as my battery pack was almost discharged I couldn't save them onto a mag card.

Who knows, perhaps some kind of PC program could be designed one day to transfer information between the HP-67 and the PC via the 67 power supply.

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