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Just these days I found a very old thread - from 2002(!) - where Gene offered to spread those cards thru volunteers who are willing to do the copy work.
At least two members were found.
The thread is here: https://archived.hpcalc.org/museumforum/...14652.html

Maybe somebody received these cards or even was one of the volunteers and still have a copy of those cards. Would be interested in a copy if affordable ;-).

Andi (Germany)
(10-09-2021 04:14 PM)AndiGer Wrote: [ -> ]Maybe somebody received these cards or even was one of the volunteers and still have a copy of those cards. Would be interested in a copy if affordable ;-).

.
It must be stressed very strongly that those NNNs can be extremely dangerous and you'll destroy an HP-97's printhead (unrecoverably burn out) if you accidentally print one of them.

This happened to me 40 years ago with one of my firm's HP-97, and I still remember the extreme pain I felt when I realized (by the smell !) that I had (unintentionally) destroyed its printhead.

This can easily happen if you don't realize there's one of those killer NNNs stored somewhere in either the stack (say stack T) or some storage register (say RE), totally out of view, and then, once you've forgotten about it, try to absentmindedly print the stack or the registers.

As this has a non-negligible probability of happening by mere accident, I'd suggest that you never, ever get one of these killers on any HP-97 by reading some cards or otherwise, or Murphy's Law will eventually do its thing and you'll be very, very, very sorry.

Not worth the risk, it's like taking a selfie while hanging on one hand 300 ft. high over the ground: if something goes wrong, the consequences are far too serious to be worth it.

Regards.
V.
How do these cards work, how is it possible to display words?
Well, how did HP get the word/abbreviations:


Crd

Error


to display; by using NNN’s non-normal numbers. Of course a lot more to it than that.

Bernhard’s LP HP 29 board has replaced, if desired, all the key codes in program mode with the Alpha equivalents creating characters by ”tricking” the 7 segment display.

Cheers, Geoff
Tony's replacement CPU boards support some text. It's possible he'll provide a cut off to prevent burning out the printer too.


Pauli
(10-10-2021 12:04 AM)Geoff Quickfall Wrote: [ -> ]Of course a lot more to it then that.
Cheers, Geoff

Yes, that is what my inquiry was about: the "a lot more to it". It has probably been explained by someone in detail before and a link to that explanation would be very welcome. I am also curious about how it can destroy the printer. Or is it some kind of "secret knowledge" that no-one is supposed to talk about?
(10-10-2021 01:57 PM)Kees Bouw Wrote: [ -> ]Yes, that is what my inquiry was about: the "a lot more to it". It has probably been explained by someone in detail before and a link to that explanation would be very welcome.

All about HP-67 NNNs

Quote:I am also curious about how it can destroy the printer.

By leaving the printhead's thermal elements on for far too long. They first burn the thermal paper to a crisp, then immolate themselves.

Quote:Or is it some kind of "secret knowledge" that no-one is supposed to talk about?

Conspiranoid much ?

V.
Quote:I am also curious about how it can destroy the printer.

Quote:By leaving the printhead's thermal elements on for far too long. They first burn the thermal paper to a crisp, then immolate themselves.

The PIK chip (afaik) only accepts 4 or 6 bit print data depending on the command sent to it. There are only two types of print command sent to the PIK from the 97 even though a few more are available, either way they are all interpreted as a maximum of 6 bits inside the PIK.

There is no way that sending the data from the C register should kill the print head as it will be internally formatted to 6 bits as an index for the 64 character ROM table lookup. I originally thought the table overflowed with dodgy data, but thinking more, that should not happen.

I'm not 100% sure but the only thing I can think of with these NNN's being sent to the printer is that somehow there is no End Of Line character send in the data stream and some uncontrolled loop starts inside the PIK chip which keeps the heads on too long. HP mentioned that this character MUST always be sent to the PIK as part of a print line. The other thing that might happen is the print carriage jams hard against the opposite side of the printer frame and stalls the motor causing other damage like stripping the soft idler gear.

If I had one of these NNN numbers, I could inject it into the emulator and see what happens when it is processed by the HP print code.

cheers

Tony
(10-10-2021 02:16 PM)Valentin Albillo Wrote: [ -> ]All about HP-67 NNNs

Valentin,

Thank you VERY much for that link! On the page I read that a lot of detailed information can be found in the PPC newsletters and documentation (http://www.pahhc.org/ppccdrom.htm). Many years ago I bought the archive on cd-rom (forgot I had it actually) so I checked it out and wow, in those days without computers and internet people were really getting the most out of their calculators!

Kees.
(10-09-2021 04:14 PM)AndiGer Wrote: [ -> ]Just these days I found a very old thread - from 2002(!) - where Gene offered to spread those cards thru volunteers who are willing to do the copy work.
At least two members were found.
The thread is here: https://archived.hpcalc.org/museumforum/...14652.html

Maybe somebody received these cards or even was one of the volunteers and still have a copy of those cards. Would be interested in a copy if affordable ;-).

Andi (Germany)

I'm pretty sure that I was one of those volunteers, and I have these cards somewhere.

Since you're interested, I'll look around to find them. And work to get an HP-97 working well enough to read/write cards.

In the meantime, you can see some examples at these links:

Seasons Greetings: https://www.youtube.com/watch?v=libGuLCyikY\
Coca Cola: https://www.youtube.com/watch?v=3FN5eCvkoPM
HP Commercial: https://www.youtube.com/watch?v=0z8UiZz2Bm0
HP Poem: https://www.youtube.com/watch?v=JMuMz623ub4
Living Words: https://www.youtube.com/watch?v=_jXGb-CR1Tg
Would be cool to have a copy of those cards. PM sent
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