Is this from an HP-97s?

The Museum of HP Calculators

HP Forum Archive 21

Is this from an HP-97s?
Message #1 Posted by Marcus von Cube, Germany on 7 Feb 2013, 4:32 p.m.

I'm asking in the name of someone else who is no longer on this forum:

Quote:
What is this connector on hp-97?
http://i851.photobucket.com/albums/ab76/hp41cx/2013-02-07132644_zpsf2667f89.jpg
http://i851.photobucket.com/albums/ab76/hp41cx/2013-02-07132623_zps6e5b6768.jpg


Re: Is this from an HP-97s?
Message #2 Posted by Harald on 7 Feb 2013, 5:11 p.m.,
in response to message #1 by Marcus von Cube, Germany

I don't know what is going on with all the wires, but the PCB looks like the one in my HP97.

Re: Is this from an HP-97s?
Message #3 Posted by Eric Smith on 7 Feb 2013, 5:57 p.m.,
in response to message #1 by Marcus von Cube, Germany

Not a 97S. Looks like someone hacked up a 97 to connect an external keyboard.

Re: Is this from an HP-97s?
Message #4 Posted by marais on 8 Feb 2013, 2:21 p.m.,
in response to message #3 by Eric Smith

I have a 97 converted to a 97S by adding a connector with multiple wires inside. I don't know the exact wiring, but I would think this is exactly what happened here. To the best of my knowledge, both calculators have the same hard- and software, and only the Centronics plug is missing on the 97.


Re: Is this from an HP-97s?
Message #5 Posted by Eric Smith on 8 Feb 2013, 3:47 p.m.,
in response to message #4 by marais

The wiring shown is not for the correct set of signals for a 97S conversion.
Also, the difference between a 97 and a 97S is a LOT more than just wires and a so-called "Centronics" (actually "Delta Ribbon" or "CHAMP") interface connector. There's a whole BOX full of electronics that interfaces between the base calculator and the interface connector.
Edited: 8 Feb 2013, 4:22 p.m.

Re: Is this from an HP-97s?
Message #6 Posted by aj04062 on 8 Feb 2013, 9:46 p.m.,
in response to message #5 by Eric Smith

Eric,
I have a 97S and I just picked up another 97 that someone wired up a serial connector to. Was there a way to duplicate the 97S like this?

Re: Is this from an HP-97s?
Message #7 Posted by Eric Smith on 8 Feb 2013, 10:06 p.m.,
in response to message #6 by aj04062

Sure, if you build a clone of the external box. It contained two boards full of SSI/MSI chips.
Or, using modern technology, you could probably do it using a PIC microcontroller, but the trick would be to write the firmware.

Re: Is this from an HP-97s?
Message #8 Posted by Katie Wasserman on 9 Feb 2013, 1:25 a.m.,
in response to message #6 by aj04062

Quote:
Was there a way to duplicate the 97S like this?
Yes, here's how.

Re: Is this from an HP-97s?
Message #9 Posted by Tom Lianza on 11 Feb 2013, 11:34 p.m.,
in response to message #8 by Katie Wasserman

katie, what would we do without her!

Re: Is this from an HP-97s?
Message #10 Posted by Eric Smith on 12 Feb 2013, 12:20 a.m.,
in response to message #9 by Tom Lianza

There's no question that it's impressive work, but it doesn't seem to me that it's a "duplicate" of the 97S.

Re: Is this from an HP-97s?
Message #11 Posted by Katie Wasserman on 12 Feb 2013, 2:38 a.m.,
in response to message #10 by Eric Smith

Agreed. There's much in the 97s pod that's not being duplicated at all. Monitoring and decoding the instructions to determine when the flags are set and cleared is the big missing piece. The pod also reads a full word of BCD data in parallel and outputs it (serially) to the calculator. While this would be an easy addition to the program, it would require some additional hardware, or a processor with a lot more input pins.
I was just answering AJ's question:

Quote:
Was there a way to duplicate the 97S like this?
As 'yes' there's a way and pointing to a description of roughly how to do it not claiming that I had done it all.

Re: Is this from an HP-97s?
Message #12 Posted by Katie Wasserman on 12 Feb 2013, 2:21 a.m.,
in response to message #9 by Tom Lianza

:-)
Hi Tom! It's been a crazy long time, hope all is well with you.


Re: Is this from an HP-97s?
Message #13 Posted by Tom Lianza on 12 Feb 2013, 8:03 p.m.,
in response to message #12 by Katie Wasserman

Busy with lots of things that are not calculator related, but my collection (most of it) made it up to my new office in the barn and I do get to see them on a regular basis. I still have a Wang that I need to bring back to life, but that is a long term project.

[ Return to Index | Top of Index ]

Go back to the main exhibit hall