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Experience with the disintegrating HP-41C-system (and batteries).

Posted by Guido Abts on 20 Aug 2004, 4:13 a.m.


Please, 2 questions: - I have almost 100 HP-41 magnetic cards (82104A). Can they be read (or written) in another HP-calculator. Or are the almost useless and only ready for the trash-can? - Why should it have been so difficult in the 80's to use standard battery types or to build the possibility to use the recharger without the batteries?

And a little bit more history…

I read somewhere on this site that in the 80's in Belgium you had to deliver the old rechargeable battery pack before you could get an new one. The real story however is a little bit different… In a time that there were amazing and also expensive rechargeable battery packs for the popular HP-41 and HP-82143A-printer it could happen that you bought a new pack that seemed to be useless because of under loading or defect. So far, so good. The first time I had this problem for my printer. But, it seems also that some bad guys brought back their old pack. So the next time – and because of the rumours – I refused to buy a new battery pack for the HP-41 without testing it in the store. It seemed to be OK. You can never be too careful.

Battery pack for HP-41. My card reader HP-82104A vanished this year (5/2004). It was a shock. In fact I didn't use him anymore for several years. He has never worked so good for the first 2 cards, and suddenly there was a lot of dirty sticky glue on the surface of the 3th magnetic card. And also on the cleaning card… Yes, I think the word "gooey" elsewhere on this site will give the right meaning. I dropped it in the trash-can. Probably the card reader was the very weakest part – and relatively the most expensive too – of the HP-41 system. This should have been better done in the development department. Especially for the card reader HP developed a rechargeable battery pack with his own recharger. In the period 1981-1992 there was no need for more than 2 rechargeable battery packs. So, it was about 1992 when I heard there were no battery packs any more since a long time. Since then I use the Varta 4001 LR01 Lady/N cells (the 4001-type, MN9100). They seem to last for almost 10 years in low using circumstances and without a card reader.

Battery pack for HP-82143A printer. The 2d battery pack for the printer was good for 18 years until 7/2004 - however not frequently used. The 1st pack was only 4 years active… I found the following solution to keep the printer nowadays on-line… I hope at least as long as the nice blue (82045A) and black (82175A) thermal paper is available in my desk… Only 6 rolls left, and yes, I had no more than 12 rolls since 1987, 300 m of paper…

The recipe to keep the printer alive. Take 4 rechargeable batteries R14NC-P, 1.2V – say 2.5 Ah. I think it will work with R6 or R20 too. You put the batteries together (the difficult part) i.e. in an old transistor radio with a battery house. You connect the + and – poles with the printer diodes. A piece of electric cable and cupper strips will do it. When you get 5.8 V in a series of 4 batteries and 6.5 A for each battery the printer will work for a quarter. Then the BAT-light will light up when printing. It seems that 5.2 V and 5 A is not enough anymore. So I connected the recharger from the HP-41 battery pack simultaneously and … it works! Without batteries the calculator gives "PRINTER ERROR". In fact I mislead the calculator. She doesn't see that the power comes almost from the recharger. What a wonderful time…

With friendly greetings, Guido Abts Belgium

Edited: 21 Aug 2004, 4:22 a.m.


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