For Sale HP-41CX + accessories

[MichaelHarwood]

HP-41CX for sale

Accessories:

* original case + foam rubber insert
* HP-41C Manual NOTE: this is NOT 41CX manual. I bought the calculator second hand in the early 2000s and it came with this manual.
* HP-41CX Quick Reference Guide
* Math Pac Module (purchased 2009 on Ebay)
* Math Pac Module manual
* 4 keyboard overlays
* one black holder that holds the overlays and three expansion modules
* Card reader. The card reader was repaired a number of years ago so that the rubber wheel is not gummy any more.
* 25 cards. They are in two separate packages (9 and 16 cards). It seems that I used 9 cards and the 16 cards are blank.

The calculator works fine. However, I have used it less and less over the years and have hardly used it at all since the pandemic. I am now retired and I need to sell it so that someone else can enjoy it.

I believe that the case is not screwed shut (none of them are?), and, alarmingly, it started opening a couple of times at the top. This is the reason that I bought the Math Pac module. Keeping the math module in place fixes this problem.

Sadly, I forgot a set of batteries in my calculator and they corroded. I've tried to clean as much of the corrosion as I can. You can probably do an even better job. The calculator still works.

My biggest issue over the years, the one that drove me completely nuts, was the N size batteries. They're very expensive and they don't last long once the card reader is being used. I tried various ways to fix this.
My first idea was to get a second battery holder, remove the separating plastic and then put in a nice, large, cheap 6V battery (Duracell 7K67 battery). However, I had trouble reliably connecting the +/- of the battery to the calculator.
My second idea was to have an external power supply, and solder wires to the + and - terminals of the battery holder. I did it in such a way that the N batteries would still fit at the same time. Problem: the two 6V power adapters that I tried didn't work. I suspect that they have too much AC ripple on the 6V.
Third idea: instead of an external 6V adapter, get 6V external batteries (e.g. 4 D cells). I never got around to doing this. Using AA would be better -- less bulk.

Anyway, this explains what you see when you look into the battery compartment (see attached photos):

* There's a little corrosion. The -ve terminal looks bad, but a lot of it is solder.
* There's a red and black wire soldered to the +/- ends, and the wire snakes out the port.
* One of the spring tops broke off (due to corrosion?). The rest of the spring is still sufficient to make contact with the N cell.

With appropriate tools, you could remove the solder and extra wires and restore things to how they were.

Card reader:

I purchased 4 N batteries on 22 March 2024 and tried it out, after not using it for perhaps 4 years. There were some "malfunction" messages, which means that the head needs cleaning with a cleaning card. I don't have one.
I tried a few times and was able to get a program card read in as well as my status card (both sides). What happens is that it doesn't always recognize that there is a card in the reader, so you have to wiggle it in and out a bit or else push it in more firmly in. Out of the 8 times I tried to read a card, it worked 50% of the time. I think someone who knows more about this would be able to get it working, or maybe just more use of it would fix the problem. Some cards had check sum errors - which might be the card or the card reader.

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IMAGES: There are four photos. See https://imgur.com/a/mqiCQ5N
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I'm asking US$200 for everything. Since I live in Canada, I imagine that shipping will be about $30 to anywhere in USA and Canada. I'll make sure that it is well packed and has a tracking number.

Please feel free to ask for any more information.

[MichaelHarwood]

Interesting. No interest here at all.

I guess I'll try Kijiji.

[johnb]

(03-25-2024 11:17 AM)MichaelHarwood Wrote:  Interesting. No interest here at all.

Not entirely "none."

Are you at all amenable to breaking up the kit and selling individual items?

[Johnboy]

From the description, it sounds like the calculator may have a issue with the case screw posts. Also, is it a "half nut" or "full nut" ?

Thanks
John

[Steve Simpkin]

(03-25-2024 11:30 PM)Johnboy Wrote:  From the description, it sounds like the calculator may have a issue with the case screw posts. Also, is it a "half nut" or "full nut" ?

Thanks
John

Judging from the photos he provided, it appears to be a "half nut" version.
What is HP-41half and full nut

[MichaelHarwood]

(03-25-2024 06:25 PM)johnb Wrote:  

(03-25-2024 11:17 AM)MichaelHarwood Wrote:  Interesting. No interest here at all.

Not entirely "none."

Are you at all amenable to breaking up the kit and selling individual items?

I don't think it's a good idea to split it up - except for the manuals. I'm happy to sell those separately. What would I want with a card reader with no HP-41? And to have the calculator without the card reader makes it such a pain to reenter programs if the memory gets erased.

[MichaelHarwood]

(03-25-2024 11:30 PM)Johnboy Wrote:  From the description, it sounds like the calculator may have a issue with the case screw posts. Also, is it a "half nut" or "full nut" ?

Thanks
John

I've been trying to figure out if it's a half-nut or full-nut by looking at photos. But I know nothing of the distinctions. The serial number is visible on one photo if that helps.

My philosophy is to not open it and see how things connect inside. It works fine and I've got it so that the case doesn't accidentally start to open.

[Steve Simpkin]

(03-26-2024 08:27 PM)MichaelHarwood Wrote:  

(03-25-2024 11:30 PM)Johnboy Wrote:  From the description, it sounds like the calculator may have a issue with the case screw posts. Also, is it a "half nut" or "full nut" ?

Thanks
John

I've been trying to figure out if it's a half-nut or full-nut by looking at photos. But I know nothing of the distinctions. The serial number is visible on one photo if that helps.

My philosophy is to not open it and see how things connect inside. It works fine and I've got it so that the case doesn't accidentally start to open.

The following page mentions some of the differences between the full nut and half nut versions and how to tell them apart from looking at the display.
What is HP-41half and full nut

Judging from the photos, it appears to be a "half nut" version.

[MichaelHarwood]

I wonder how much demand there is for this calculator. What price would someone want to pay for it?
Ebay sells them for around $400! Though there is one for $200

[rprosperi]

(03-31-2024 12:41 PM)MichaelHarwood Wrote:  I wonder how much demand there is for this calculator. What price would someone want to pay for it?
Ebay sells them for around $400! Though there is one for $200

eBay sells FULLY WORKING units for that much, yours isn't one like that.

From your description, the upper posts of your 41 are broken ("I believe that the case is not screwed shut (none of them are?), and, alarmingly, it started opening a couple of times at the top. This is the reason that I bought the Math Pac module. Keeping the math module in place fixes this problem.") which is a difficult thing to repair and takes expertise and experience to do it right the first time. This greatly reduces it's desirability and value, though it is certainly better that you disclosed it now, rather than having to a rtn/refund later when the buyer discovers it.

The extra accessories definitely add overall value to your bundle, but if a buyer doesn't want to deal with a broken machine, even the extras don't make it appealing enough.

Many crazy sellers list dead HP machines 'AS-IS/For Parts' for prices approaching a fully operational one, knowing some community guys can fix them for cheap and then sell them. Such listings are generally ignored and then eventually acquire a 'Make an Offer' option and are sold for a small fraction of the asked price. I know as I've bought some like that.

If you're in a hurry to sell it, I'd say go to eBay or FBMP, but if you can wait, someone will likely make you a reasonable offer before too many more weeks go by.

Good luck!

[MichaelHarwood]

(03-31-2024 03:47 PM)rprosperi Wrote:  From your description, the upper posts of your 41 are broken [...]
Good luck!

Thanks for the information. I wonder if the posts were broken when I bought it. I didn't think that the HP-41C had screws holding the top and bottom together, so I thought that this was a normal issue. I read somewhere that they were just clipped together. However, it must have been referring to some other part of the calculator.

[johnb]

(03-26-2024 08:26 PM)MichaelHarwood Wrote:  

(03-25-2024 06:25 PM)johnb Wrote:  Are you at all amenable to breaking up the kit and selling individual items?

I don't think it's a good idea to split it up - except for the manuals. I'm happy to sell those separately. What would I want with a card reader with no HP-41? And to have the calculator without the card reader makes it such a pain to reenter programs if the memory gets erased.

Precisely my thinking. I have an HP-41cx in good working condition but no card reader.

However, in the interests of community goodwill, I agree with the other posters that you should seek to maximize your profit so you have more nickels in your nickel-jar to spend on other HP fun.

[MichaelHarwood]

(03-31-2024 10:07 PM)johnb Wrote:  

(03-26-2024 08:26 PM)MichaelHarwood Wrote:  I don't think it's a good idea to split it up - except for the manuals. I'm happy to sell those separately. What would I want with a card reader with no HP-41? And to have the calculator without the card reader makes it such a pain to reenter programs if the memory gets erased.

Precisely my thinking. I have an HP-41cx in good working condition but no card reader.

However, in the interests of community goodwill, I agree with the other posters that you should seek to maximize your profit so you have more nickels in your nickel-jar to spend on other HP fun.

Good evening. Are you implying that you would like to buy the card reader and the cards?

[MichaelHarwood]

UPDATE

The card reader now works much better. I just had to use it a couple of times.

For some reason the card reader clips do not always attach firmly to the calculator. I wonder if a spring is soft.

[MichaelHarwood]

SOLD

For US $150