HP 41CV defective

Hi all!
I bought recently a "fullworking" HP41CV on e-bay , from a collector.
My plane was to find a good base (donor) to build a HP41CL, 'cause my only fullnut calculator is a CX and I don't want sacrificate it. I was and I am still waiting for the CPU that is on the way.

When I received this calculator I've noticed and informed immediately about the seller, the presence of a little corrosion on the first battery contact on the left, but the seller confirmed that the calculator had no problems (infact it was working, as I was able to test it). I left inside n.4 new cells LR1 brand ENERGIZERS.
After a couple of weeks I took again in my hands the machine and found with no reasons a "BAT" alarm. I chahged the quartet with another I had in my CX and after a couple of day (calculator in rest) I found the same problem. I bought another fresh quartet "DURACELL" brand and past a couple of day the same issue always, ofcourse, while the calculator was OFF!

To avoid at least to throw other money in cells testing the calculator, I recelled a battery pack (that should be useful in wiew to enjoy a HP41CL). When completely charged, after a night inside the calculator turned off, the pack was completely discharged, when trying to turn it ON the calculator shows no sign of life!

I must assume that there is a problem, sure, with the calculator, I mean it's defective, what do you think about?

Now I can't even open the calculator to investigate, cause I starded a case with e-bay-paypal and see please, here below, what the seller answered:

quote ["I don't accept your behaviour since the beginning.
1> I certify that this calculator was working perfectly and described exactly as in the auction.
2> It is the first time I heard a "pseudo battery issue" for a classic HP 41 and again it this calculator worked well before so I don't see what could be the problem for this one..
3>I encourage Ebay and Paypal Team litigation to read your previous posts which where extremely interesting !
You told me that your plan was to OPEN this calculator and CREATED an HP-41CL.

Have a look on this HP-41 Forum : "http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv020.cgi?read=185434" and you will understand that you should not use classic cells or even rechargeable cells as "the battery drain from the new 41CL is some 10 TIMES GREATER than a normal 41 WHILE OFF".

You will see that all HP-41CL users are avoiding theses cells and worked for example with USB Cable to sustain power.
4> I don't know what are the origins of your cells and if they are partially discharged or not but I don't care really as it is not the issue.

You received now this calculator almost ONE MONTH AGO!!!!!, and since this time you tried to create litigation or doubts around me so I have really some questions marks on your honesty. First , it was contacts, then Screws, now Batteries consumption which is irrelevant!
You've said you will open it and I am quite sure you did it which is now your responsability as I will not able to check if you didn't change or replace any parts!
As a conclusion, I refuse to be charged for any claims and I am asking EBAY and PAYPAL Teams , first to close this claim and then to not proceed to any reimbursement to this person, because I don't see the reason why!
I can help them to go through dedicated forum for this calculator to see If I am Right or not.
PS: I am going to sell more HP-41 in the future with defaults and I will mention them accurately. No doubt
regards" ] quote

Never, I underline, never I've opened the calculator and the "interest" and my questions recalled by the selle about screws (eventually cracked post, means) were, I think, justified, read please below my words:

quote:["I think that the calculator is quite in a good shape except for the things I've noticed, I see that the corrosion has affected expecially the first contact (a small hole, but if you assure that it will not grow up (as I personally think) for me there are no problems to take it as is: it works!
But you have not yet answered to my indirect question about eventually cracked posts: do you have already opened the calculator?
I am going to make a 41CL, for that reason I was looking and I bought your calculator.
I must open it to make the transformation and I'm scared to get problems with cracked posts, a issue which is not easy to solve, I prefere to don't have such a one.
If you assure there are no problems, I trust you and keep the calculator, without any more questions, let me know, please.
As I can read in your description you are a collector, so you know what I mean."]quote

I ask you please for your opinion, technical advices for the issue and more are welcome.

Aurelio Traverso

Edited: 13 May 2012, 3:38 p.m. after one or more responses were posted



I bought some HP41's, a few defective, or destroyed - and in some cases, intentionally destroyed or wrongly modified or cannibalized, one of them sold by one of the non-regular contributors here... -. You know what? Flock them! I now have at least three carcasses I can take parts from so the other HP41's will live longer. Will not sale them, will not throw them away. I have already used parts of them to feed others needs.

Now for the little one: I'd open it ASAP, battery leakage and consequent corrosion must be stopped quickly. Matter of fact, except for a defective LCD module (somehow rare), I can see only two reasons of this excessive current consumption:

1) ruined logic board; I have already found a defective one with the LCD controller, a RAYxxxx-series IC, that got warmer enough you could feel it in your finger tip. It has some bipolar transistors etched on it, and if any of them goes crazy... Once replaced, the calculator restored its standard power consumption.

2) most likely, if not the above, consider that the battery leakage reacts with cooper and resulting material from this reaction may become conductive and connect different board tracks or component terminals.

I'd keep it and disassemble it ASAP. Then I'd take the logic board apart and carefully inspect the remaining of the calculator, which is what you need for the CL board. Pay total attention to the battery contacts/module contacts assembly, this is very important item.

Somehow the seller is right: you will not use the original mainboard anymore once you get your CL board. But you are in your rights asking for a fully working equipment, as you bought one. If the fighting and consequent headache worth it, go for it.

P.S. - I do not know the seller, do not know who is it indeed, I just wrote this follow-up based on the facts exposed in the this thread.


Luiz (Brazil)


I'm a technician Luiz, not a lawyer, so that the first was to open it and find the problem....but as you wrote is in my "rights asking for a fully working equipment, as I bought one."
I payed for a fullworking equipment just to have not worries.....

Edited: 13 May 2012, 4:03 p.m.


but this sounds like a defective capacitor. If that's the case, these are easy to replace.


Thank-you maybe could be easy to find and to fix this issue, but I would like not to open the calculator before to have defined the situation with the seller: actually I would like to send him back the calculator and, ofcourse no doubt, in the same conditions I've received it!
I'm pretty sure that the seller read and will follow this post, 'cause he is a member of our community. For this reason I would like to share the pictures which shows the defectes of the calculator he sold me and I've noticed immediately, when I received the calculator; the nosense is that he now even rejects those complaying "certifying" that the calculator is in in a perfect shape!!!

Give please a glance to theese pictures:

and tis is what I wrote him just after received the calculator noticing what the pictures show(16th april)

quote Aurelio: [Hello, I've received today the calculator!
As from the first glace seems that the four ports are OK, but the contacts are not "Contacts en très bon état.". the first on the left is a little corroded, on the third there are traces of green, while 2^ and 3^ are OK; why you did not mention that in the description of the calculator? You have not seen this issues before the sale? I would like to open it to check inside if the problem is extended or not to the rest of the caculator, but I don't do it because I don't know if the calculator is affected or not by a cracked posts issue. Did yuou check it? It seems, but maybe I'm wrong that the label on the bottom of the calculator has been reattached, isn't it?
let me know thanks.] quote

and then read his last words in the paypal litigation, form so your own opinion about:

quote seller[[Yes, please proceed:
1- ask for the community the reason why this calculator could drain batteries. I don't want to read ings like "i think so or I believe....." but facts and figures only.... And don't tell me that contacts were corroded!it is not true!

2- I certify again that this calculator was cosmetically nice and worked perfectly and could not certified what you did during this month with it (calculator opening, parts changed or removed)

3- if and only if for some reasons I could decide to accept any transactions, as I don't feel guilty, wewill proceed as follows

- I am waiting feedbacks from the HP community

- you will send me back this calculator at your charge and I will check by opening this calculator at your risks! If there are no crakles , problems with screws, contacts issues ,spares changed and so on.
I noticed you said you bought hp-41 "meanwhile" and it make me more and more nervous about the fact You could change spares. if i see any problems, I will not accept your return and will not reimburse you

- I will reimburse you only calculator and not my shipping costs . Again, i don't feel guilty and I don't
want to support any costs,

- i don't want that paypal support any charges because of you.....

I spent tens of thousands euros on ebay since the beginning
I can spend 2000 euros for an hp-41 turbo without problem with the ebayer!
It is not you and your 105 euros of litigation who will trouble my life .

But for principle, I will not let you so easily contest this transaction!]quote

Well, I hope that pictures at least will satisfy this guy and just to avoid any misunderstanding I notice here that the calculator I bought "meanwhile", is arrived from Germany only yesterday morning: it is really in a good shape, works great, as I can see, any pictures of it, just a courtesy to him and please believe. I'M THE ONE NERVOUSE, NOT YOU, CAUSE OF YOUR UNDEFINIBLE BEHAVIOUR!

Notice thaT another HP41C is on the way from the USA and i want say that this in my e-bayer experience I met throuble with vety few people, If I think that it should be easy and smooth' cause of the "eureopean contest", I'm pretty disppointed for this unbeliveable transaction!

Just to give another answer to the seller I'm glad that he can spend a lot of money without problems, for me this HP41CL project means a lot of sacrifice and even the 105 EUROS he wrote means for me no holidays this year, no pizza with friends, no coffe at bar, I have no Rolls royces..........I haven't even a car, but I'm proud to be know as a honest people and that's all!

Apologize for so along post.


Edited: 15 May 2012, 5:32 p.m. after one or more responses were posted


you could post the auction number, so it's easier to judge if the description could have allowed this corrosion.

If the seller sold the item as "nice and fully working" I'd say file a complaint with PayPal - the corrosion is a major technical flaw, pretty much unfixable (unless you have a new flex strip).

Suggesting that you caused the corrosion (the defect certainly took several months, if not years to grow that large) or exchanged parts is "unfriendly" (a heftier wording would be OK) and tends to appear fraudulent. Again, my opinion might change with reading the auction description...


Hi Frank!
I've not linked the auction so as I've not published the name of the seller just for a respect of his "privacy" , this is my policy 'cause by default I trust in people and I expect the same by him, I mean I whis we can solve still toghether and peacefully yjis embarazing situation.
What I can do is only to quote here the description of the item in the auction and say also that there was only a small picture reporting the front of the calculator, of the cells LR1 holder, and of the documentation on CD which I have not requested to send because for me useless (I've already the MoHPC DVD

Usually in theese case I ask to the sellers for more detailed pictures, but this time for many reasons: his feedback, the fact that he presented himself "as a collector" and we already e-mailed toghether when he just sold the previous calculator and told me he was listing another piece of his collection, I believed simply to bid with confidence..

Here is the description

quote[VERY NICE CALCULATOR HP-41 CV N° 2 ( 41 CV 41-CV 41CV )

Very Nice Calculator Hewlett Packard HP-41 CV from my collection N°2 (N°1 and N°3 already sold)

Full working (Ports tested)

Connectors OK

Documentation in English and French in Electronic Format

* HP-41CV Manuel d'Utilisation et guide de programmation en Français
* HP-41CV Aide Mémoire en Français
* HP-41CV Operating Manual a guide for the experienced User English
* HP-41CV Owner's handbook and programming guide English
* HP-41CV An Easy Course in programming HP-41CV English
* HP-41CV Mcode for beginners English
* HP-41CV Programmer HP-41 en Français
* HP-41CV Synthetic programming Easy English

Vends très belle calculatrice Hewlett Packard HP-41 CV issue de ma collection N°2 (N°1 et N°3 déjà vendues)

En parfait état de fonctionnement (Les ports I à IV ont été testés )

Contacts en très bon état.

Livrée avec son compartiment à piles (Type LR1) que vous trouvez facilement chez les photographes ou bien des batteries rechargeables du même type.

De même est livrée en format électronique la documentation suivante :

* HP-41CV Manuel d'Utilisation et guide de programmation en Français
* HP-41CV Aide Mémoire en Français
* HP-41CV Guide pour utilisateurs expérimentés Anglais
* HP-41CV Manuel d'Utilisation et guide de programmation en Anglais
* HP-41CV An Easy Course in programming HP-41CV en Anglais
* HP-41CV Mcode for beginners en Anglais pour les courageux!!!!
* HP-41CV Programmer HP-41 en Français
* HP-41CV Synthetic programming Easy en Anglais]quote

Hope this help you


Contacts en très bon état.

Well, they are without doubt in a very bad condition, and it's impossible to happen within a month (even assuming that you have installed leaking batteries, which you probably didn't). So the description of the item is not correct.

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