Good grief! $56 for this part?


Hard to believe. $56 for an N-cell holder?


I was at Radio Shack the other day buying AAA cell holders do doctor up my 45, and I noticed that they had N cell holders. It looks like the one you're looking at might be integral to the battery cover though...

It kinds of makes me wonder if guy sell them on eBay without the cell holder, knowing they can get more for the parts separately.

If you can't find something at Radio Shack that works, you might try searching online...



Yeah, I know. Calculators _with_ the part can sell for less. Unfortunately, I need one myself.


You guys should watch some of the other battery holder/packs for various HP calcs. I've been outbid at least 4 times at $50+ for 29C pacs for rebuild. These guys must have a bottomless wallet. There are just a few bidders that are driving prices twice over what the same items sold for last year. It will probably go higher by the year's end. Happy Bidding!!


Okay, so it works! The box? The manual?


There is another reader out there right now selling for even more... I wonder if he wants another dozen or so at the same price?


I need a card reader to replace my broken one but the way it goes I don't think I can ever afford one. I think I paid around $160 for my card reader new in 1979.


Keep looking on Ebay. Sometimes they go for afforable prices (like $40 or under). You WILL have to take it apart and replace the rubber wheel. Instructions abound on this site and others.


That is an astonishing price but these have always been hard to get, apparently. In the PPC Journals there are discussions about battery life in the 41 which became a problem after the card reader was introduced. Users remarked that if HP would make the battery holder available as a spare part, things would be easier.

The high current requirement of the card reader motor makes alkaline batteries have a short effective life. After a relatively brief period of use there is plenty of energy to run the calculator but not enough to run the motor AND have sufficiently high output voltage to maintain the calculator memory. (I think the calculator intelligence takes over and refuses to operate the card reader when the battery voltage is below a certain level.) Using "N" NiCads in the regular battery holder was better for the card reader motor because NiCads maintain a fairly constant output voltage at high current drain compared to alkalines. But the NiCads will only run the calculator for a fairly short time because of their low capacity (150 mA-h vs >1000 mA-h for alkaline N cells) and their high self-discharge rate (need to be recharged once a month or so). This is aggravated by the fact that you can't recharge the cells in the calculator (Thank God! imagine how many 41's alive today wouldn't have survived if NiCads could have been recharged inside!) A good solution would be to have a spare battery pack loaded with NiCads so you could quickly change to NiCads when using the card reader. Apparently HP didn't make the spare battery holders available. Their solution was the rechargable pack which has even smaller capacity cells (I think 50 mA-h).

Another thing is that the springs are destroyed by battery leakage, leaving the plastic in fine shape. Somebody who used to advertise in the classified ads here had lots of the plastic holders without springs. I'd like to learn how to make those springs - what kind of wire to start with, etc. - because some of my holders have corroded springs.


Yes, I found in an old Key Notes where HP starting selling spare battery holders for the princely sum of $1.00 each!


Really! I wonder how many users knew about it? If it was widely known, you would think that people who had paid about $300 for a calculator would have bought a few extra battery holders - then there would be plenty for everybody now!

One battery holder was likely enough for most users. They last forever unless you have a bad leak. I imagine extra battery holders would have easily been "lost in the shuffle" over the years. Maybe they are with the odd socks!

I wince whenever I read the instructions for servicing the card reader on the 9100 - book says to fold a card in two and wet it with solvent - I hate to think of all those cards no longer around for me to use!


They mentioned that you could only order them through a non-standard address. Later they made them available through the regular channels.

I don't remember the exact story, but the idea was you kept your partially depleted batteries in one for general use, and then used the good pack only when running the card reader.


> I'd like to learn how to make those springs - what kind of wire to start with, etc.

easy, just steal the springs from a battery pack that is currently available (e.g. the 3 or 4 AA battery holders that are sold in RadioShack or equiv).

I used to have a backup battery pack (wired so that it would route two cables out through the side door to an external battery pack with 4 AA batteries.

Then I bought the rechargable battery pack.

The sad thing is that even though I have kept everything from my original HP 41C (one of the first), I cannot find either the second battery pack or the recharable battery pack. I must have thrown them away :-(


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