Advice needed


With regard to the HP41's and card readers, I am sure I saw in a post (but can't find it now) that it is/was considered bad to keep the card reader permanently attached to the calculator (possible damage to screw posts).Any advice from seasoned users appreciated.
I ask the question as I tend to leave the card reader attached so as not to wear the I/O block etc, as a result of a tip I saw in "Calculator Tips and Routines" by John Dearing.



Both considerations have coherent foundations, so I'll tell what I do.

It is a fact that the modules where not actually made to be inserted and removed every single time they are requested and then not needed at the moment, so plugging and removing modules too many often will surely cause abrasive, frictional wear with time. SO, keeping modules in place (and avoiding continuous replacement) will keep contacts in good shape for longer.

The card reader itself is a different breed, it not only uses the port contacts but also 'grabs' the calculator with the two plastic clips. Once it is attached, any torque over the card reader body having the calculator case as a reference system reflects as extra pulling strength on the bolts found in the top of the calculator body, closer to the LCD. Hence, depending on how the calculator is pushed, bent or twisted (urgh!), posts will suffer harder if the card reader is attached.

I plug it in only when I need to use it, I do not often leave it connected. And if needed, like when you need to run a program with card reader functions, I try to keep it in plain surfaces, transportation avoided as possible.

Hope this helps a bit.


Luiz (Brazil)

Edited: 19 Apr 2012, 6:43 a.m.


With the card reader attached the whole thing is heavier so more prone to physical damages when dropped and the weakest point - the screw posts would suffer the most.


Thanks to both of you for replying. Looks like I will be only attaching the card reader when needed.
Maybe at the time, HP thought it a good idea to keep both attached, hence the large case to accommodate both.
Thanks again


No problem. Back then such systems were often used only like desktop devices. In case they needed to get portable there was a slim chance for a need of the card reader; that's why original soft case came with a polyurethane foam piece at the bottom. Card reader was an accessory among many others. All of them quite expensive, but worth every cent.


All the advices are more than correct altough they seem to be obvious considerations but it's not so obvious and the same question I asked before many times myself and maybe others did it on this board.
Infact the calculator was sold with a "carrying" soft case designed to contain a calculator with the reader inserted and I don't think that the problems and the risks underlined so well by Luiz are to relate only to our "old" calculators, the problems exist since that time, maybe, when those machines were regularly and daily used and carryed, stressed much more than could happen nowadays. Are you agree?

Edited: 19 Apr 2012, 8:37 a.m.


Maybe at the time, HP thought it a good idea to keep both attached, hence the large case to accommodate both.

I doubt that HP ever intended to suggest keeping the two units mated together at all times. I purchased these items when they were new and never drew any such inference from information supplied with the items, nor did my personal experience indicate that such was at all a wise thing to do.

When the HP-41C* was my daily-use calculator 30 years ago, I hated the standard large foam case. I borrowed the leather case that was a option for my old HP-67. It is perfectly-sized for the HP-41C* without card reader, plus it has pockets that will store two software modules and another pouch that will accommodate the small quick-reference cards that came with many modules. Unfortunately, such cases are now cleared eBay a few days ago for $165. Though less elegant, the standard HP-67 foam/zipper case serves the HP-41C* without card reader much better than what was supplied with the HP-41C*.

I keep my 28-year-old HP-41CX in that leather case. The whole kit appears (and works) as new today as it did in 1984. It was a great machine for the time, but it's woefully inadequate today if only from its terribly limited small display.


I use the case that came with my HP-55 to hold my original HP-41C. It was a perfect fit and as I collected more 41s, I have found a couple of 55 cases on eBay to hold them. My original 41C and CV are still in good shape using these cases.



When I used the card reader all the time (back in college in the early 80's) I used to keep it attached permanently. This was particularly true with the 41C and no extra memory where I would often switch out programs. Back then I also used it in class and lab regularly and didn't much like the idea of carrying two separate devices and then having to keep track of them both. Nowadays, with most of my offline storage being on floppy disc and most of my use being at home I rarely attach the card reader.




Back in the old days I usually kept the card reader attached all the time. No problems at all. When I occasionally took the card reader off, the HP-41 looked small, I was not used to seeing it like that.

The Wand tends to be inserted as needed and then removed. I have not encountered any problems with that either.

The only problem I have seen is that frequent opening of the HP-41 and not being cautious enough when putting it together again, cause wear in the screw posts, which is part of why my old CV now is a little bit unreliable.


I suggest by the way to never put them toghether into the zippered case, because to take out the calculator is necessary to pull it(obviouvsly kept by the reader, I don't see other way): it can damage the two springs which lock the raader to the calculator.

Edited: 19 Apr 2012, 12:29 p.m.


That is not a problem if done right. I pull the case open a bit to avoid scratching the display with the zipper and give it gentle shake to bring it out partly, then just take it out. The added weight helps. I did that several times per day for years.


Right, again! ;-)
Seems like we did the same things: usually the shake isn't needed at all, gravity is enough...



Back in the old days I usually kept the card reader attached all the time. No problems at all. When I occasionally took the card reader off, the HP-41 looked small, I was not used to seeing it like that.

The Wand tends to be inserted as needed and then removed. I have not encountered any problems with that either.

Same impressions here, kept them together almost always for more than 20 years; no problems to report.



I've regularly used my HP-41C with quad memory and the attached card reader since Jan 1980. I can probably count the number of times the reader has been removed on one hand——well, maybe two hands.

I've used the calculator in environments around the world from the jungles of Panama (jungle survival course) to the ice of Antartica, as my standard personal equipment as an aircrew member on USAF C-141 aircraft (used for aircraft performance and weight & balance). It was carried in my helmet bag along with O2 mask, flashlight and other aircrew paraphernalia. Only once did it fail me——when I inadvertently left it overnight on the aircraft at a base in Alaska in -30° F weather. When it warmed up, it performed normally.

So, draw your own conclusions relative to the added mass of the card reader if left attached to the calculator.


Hi, Cheyenne.

Have you tried the Financial Program for the HP41C? Just would like to know if it fits your needs. I have not yet posted the final list, but it totally matches the ones from the printer.


Luiz (Brazil)

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