HP Forum Archive 09

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HP-41 internal upgrade. ???? Message #1 Posted by Daniel Sancho on 10 Jan 2003, 6:23 p.m. When I buyed my actual HP-41CV I find inside a circuit: I put here two images: http://www.teclas.org/HP-Question.htm Can anybody tell me what is? Thanks. Daniel

Re: HP-41 internal upgrade. ???? Message #2 Posted by Vieira, Luiz C. (Brazil) on 10 Jan 2003, 7:49 p.m., in response to message #1 by Daniel Sancho Hi; I am not sure about it, but the most common "upgrade" is the speed-up circuit. As the IC's are scraped and no ID to confirm, the best shot is to redraw the connections and check with the original (I should dig-in these five PC's and nine hard drives... but I'm needing it, too.) Anyway, it's also normal to find a switch, usually a magnetic switch or a dip-switch, to "start" the faster clock. Have you found something like this? I also heard that, depending on the speed-up design, turning the calcualtor ON with an specific key pressed would toggle from speedy to normal. Anyway, let's hear form the others. I'm curious, too. Best regards.

Re: HP-41 internal upgrade. ???? Message #3 Posted by Andreas Müller(GER) on 11 Jan 2003, 4:24 p.m., in response to message #1 by Daniel Sancho Hi Daniel, try the hint of Luiz. Do a 'Beep'. Does your HP-41 'Beep' normal or faster? Then try to press 'Alpha' and 'User' at the same time. Do a 'Beep' again. Does the speed of the 'Beep' change? I think it should. Best regards, Andreas

Re: HP-41 internal upgrade. ???? Message #4 Posted by Daniel Sancho on 11 Jan 2003, 5:19 p.m., in response to message #3 by Andreas Müller(GER) Muito obrigado Luiz, vielen dank Andreas: The problem is that I can not test it because I unsoldered this upgrade as you can see in the images. That's because I like to have the machines original. But I had curiosity to know if anibody was able to say me if it is an interesting upgrade. was it a comercial upgrade, a kit,...? Daniel

Re: HP-41 internal upgrade. ???? Message #5 Posted by Vieira, Luiz C. (Brazil) on 11 Jan 2003, 7:02 p.m., in response to message #4 by Daniel Sancho Hola, Daniel; mi placer poder ayudarle. I'll post what I heard about it. I never had one of this, but I'll add one "turbo" add-on as soon as I have time to build one. What I know is that: - in some cases, it is incompatible with some clock-dependant devices; some 82104A card readers were mentioned as not working correctly with some speedy 41's - it enhances power consumption, reducing battery life. Other then these "features", it is harmless for the calculator itself. About availability, I was also told that it was fairly available in Deutschland (your 41 came from there, right?) as a kit, not exactly as a "commercialy availble" merchandise. I saw some different "versions", one of them with a magnetic switch mounted inside the calculator, aligned with the middle frame. This way, a small magnet could be used to toggle from "speedy" to normal. Others, as mentioned, used dip switch or key combinations/sequencies. That's all I know from other contributors at the MoHPC. Hope these informations are acurate (if I did not change them) and helpfull.

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