My Los Alamos Lab HP-97 looks like Gort


I just received an adaptor (thanks to a fellow forum member) for my Los Alamos HP-97.

Upon powering it, here's what I noticed:

- a single old-school red led in the middle of the display.
- Digits do not light up
- printer does not advance when requested

What the hell is this thing?

Somehow, I get the feeling that the unit is not defective but was modded to act that way.

If all the wires were open-ended, the calculator would work normally. Considering its rude behavior, I have to assume that additional mods were made on the circuit boards...

What do you all think?


Edited: 29 Aug 2009, 12:03 a.m.


I can think of two possibilities.

One, you have just armed an experimental nuclear device. Pray the light never goes out.

Two, it could be the low battery indicator.



Ha ha!

I don't have the 97 manual so I had no idea there was a low-bat indicator.


On the other hand, if the other option is the right one...


I highly recommend the museum DVD set. It contains all the manuals, and for the 97 it includes the very useful service manual.


Bear in mind that a 97 (or any of the Topcats) will not work properly without a good battery pack installed. You can't just power them from the AC adapter.

For testing, you can power them from 5V DC to the battery terminals, but be VERY careful not to get the polarity reversed.


Yes, it is the low power Battery indicator.
(Manual p45 and appendix B).


Yup, that's what you see if you don't have a good battery installed.

The seller waterhosko on the the auction site makes very good battery packs at not bad price.



That's what you see if you have a bad transistor in the main PCB ;))



To avert disaster, repeat after me: "Gort: Klaatu barada nikto"

Edited: 1 Sept 2009, 3:26 p.m.



Following up on your previous post about Gort...

I just put a new article out here describing how part of the 97S i/o pod works and building a project around that. I'll bet that Gort's plug was used for something like the clock (and other input stuff) that I describe.



Could it be done in the HP-67?


Could it be done in the HP-67

There's a very good possibility that it can with some modifications. Looking at Tony Duell's schematic, the keyboard scanning is similar but arranged as 5 x 8 matrix with some non-used keys. The control lines (DATA, RCD, STR) all seem to be used in the same way as on the 97.

My guess is that it will work with minimal code changes for the keyboard scan. The big challenge that I see is finding space inside the 67 calculator to add a chip or two.

Looking at Tony's drawings and taking this a step further, it looks to me like the same keyboard scanning control lines are used on all the "classic", "topcat" and "woodstock" machines, but changed on the "sting" and "spice" series when they combined the anode and cathode drivers on the same chip. I'd need to experiment to confirm if this is really the case though.



I'll keep the video handy. I still have to get a power pack to properly power it up. We'll see then what kind of black magic it does...

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