HP-41C* Halfnut vs Fullnut



#2

Hello out there,

Can anyone tell me what the difference between an HP-41CV "fullnut" and an HP-41CV "halfnut is? I would like to know as much as possible about this.

Why did HP redesign the calculator?
Are there advantages to one or the other?
Which is the better version to have?
Is one easier to repair than the other?
Does one have a greater failure rate than the other?
What is the difference in the guts and why the change?
Externally, what is the difference?
What are the problems with each type?
Is the change of absolutely no signficance what-so-ever?

Any help would be greatly appreciated.

Thanks


#3

Hi Todd,

the main difference is the trim around the screen.

I believe the calculator was redesigned because the electronics got smaller and they could redo the 41C* so that all the electronics could get in just one board.

I'll try to sintetise the differences as I know it.

Fullnut:
A screen with somewhat more contrast.
A bit more susceptible to fail because it's got more pieces and because of the solder-less connection between the boards.
More electronics (or at least bigger, someone correct me please)
A bit more prone to get dust inside the screen from my personal experience.

Halfnut:
A somewhat less contrast in screen by default, although the contrast can be changed in this model by software.
Less components, all integrated in main board.
More difficult to fail, but perhaps more difficult to repair in case of failure.

Besides this I don't know more. In my personal opinion there is no right or wrong one to get, but I prefer the halfnut look over the fullnut. If you are a collector, then the answer is, try to get one of each model.

I also believe that some members here can get you a more technical detail of what I mentioned about the components.


#4

I have one of each and I definitely prefer the one with sharper contrast and without the thin black "matting" with curved corners that reduces the visible LCD area. I infer that sharper contrast is Fullnut and softer contrast with matting is Halfnut?

I would be interested to learn how to change the LCD contrast in a Halfnut unit. What software does this?

Many thanks,

Les


#5

Unfortunately, as far as I know it can only be done using M-code (the '41's machine code) which means you need a RAM box (such as an MLDL) and something like the MLDL-OS ROM or ZenROM or through the HEPAX module. :-(

PS I'm with Klaus, I prefer the Fullnut display.


Edited: 20 July 2006, 8:19 a.m.


#6

James -

I am new to most of the "technical side" of these calculators, so forgive my being naive and possibly asking very basic questions.

I used to have a fullnut 41-C and with the exception of taking it apart to clean it or change the batteries - I just used the thing a lot. But that calculator is now dead.

I just got my hands on a 41-CV halfnut (after much effort and $). Since I do not want to repeat that experience, if I don't have to, I want to understand that calculator to the fullest extent with respect to knowing how it works, how to repair it, how to modify it (if I so choose to do so), where to get parts, etc, etc.

I liked the display on the fullnut and this stuff about the display being different on the halfnut makes me think that I may want to change how the display looks (I may come to the conclusion that it is just not worth the effort).

Anyway, you spoke of some hardware that you thought one needed to modify how the display appears ----

is that hardware difficult to acquire?, is it expensive?, where would I get that kinda of hardware?, and assuming I got it, how would I go about performing the modifications to the calculator (or where could I go to find out how to do it)?

Any help would be appreciated.


#7

Hi Todd

Have a look at Howard Owen's post (message #7) on this previous thread for some further details on RAM boxes and the thread in general as for the likely cost of a HEPAX module should one pop up on Ebay.

I would guess that if you are interested in using rather than collecting that the offerings from either Diego Diaz or Meindert Kuipers are your best bet.

Unfortunately that is about the limit of my knowledge on the subject - I've certainly no practical experience on delving into M-code!

Best regards and good luck

#8

Hi,

well, although cosmetically I do like the halfnut more, the dust problem is also more prevailing in the fullnut and it really annoys me.

Fortunately the dust in the screen problem seems to have been fully fixed by HP in the later units. From the 48SX on I never saw dust again and even some 42S seem to be without dust problems.

I wonder if HP modified the 42S line during it's lifetime to a better dust-proof screen?


#9

Quote:
I wonder if HP modified the 42S line during it's lifetime to a better dust-proof screen?

Yes. In 1990, the HP-42S, HP-32S, and other Pioneer-series models got an improved display. This included a recessed window, non-glare screen, taller characters, and presumably a gasket between the LCD and the window to keep dust out.

The HP-21S had this style of display in 1989.

-- KS


#10

My recently acquired and grossly overpriced 42S (a combination of the eBay market at the moment and my naivete and impatience at the time) needed the keypad cover flattened, cleaned and reglued, so there is a vulnerability now to dust getting between the window and the LCD, but there seems to be no problem with the LCD proper.

Les

#11

The electronics package was completely redisgned from a mechanical standpoint. The halfnuts are more difficult to repair but less prone to certain problems.

I don't remember all the details, but there is some description of it in the museum main mages, as well as extensive discussions in the archives, especially back in 2003 and 2004.

#12

I don't know if this is really a difference between Fullnuts an Halfnuts, but my fullnuts have a "standard number" calculator display, while the halfnuts have kind of an "alphanumeric" display. I mean the halfnuts diplay the numbers somehow streched, and the semgents do have more space between them.

I like the older display more.

#13

Part 1:

Q) Why did HP redesign the calculator?

A) To make more money.

Q) Are there advantages to one or the other?

A) IMO, from all practical standpoints, no.

Q) Which is the better version to have?

A) It's a matter of personal taste in the LCD.

Q) Is one easier to repair than the other?

A) That would depend upon what was wrong.

Q) Does one have a greater failure rate than the other?

A) My money is on the Halfnut being more reliable.

Q) What is the difference in the guts and why the change?

A) You already asked about that. Money.

Q) Externally, what is the difference?

A) The appearance of the LCD.

Q) What are the problems with each type?

A) You already asked about that, didn't you?

Q) Is the change of absolutely no signficance what-so-ever?

A) All depends upon your point of view.

Part 2:

Anyway, you spoke of some hardware that you thought one needed to modify how the display appears ----

Q) is that hardware difficult to acquire?

A) Yes

Q) is it expensive?

A) Yes

Q) where would I get that kinda of hardware?

A) Build it yourself or eBay

Q) and assuming I got it, how would I go about performing the modifications to the calculator (or where could I go to find out how to do it)?

A) Why bother?

The only thing you can do with a halfnut is to change the contrast - which requires what is now rather obsolete and esoteric hardware. This with the exception of the Clonix module. Set you back about $150 or so. Just to change the contrast? You could buy a fullnut for that.

Bottom line is that you cannot exchange the LCD or any other electronic bits between the two different versions. The only interchangable parts are the case bottom, case middle, battery tray, battery/port connector and the port covers. Okay, a couple of capacitors too.

If you like the display of a fullnut, buy a fullnut.

If you like the display of the halfnut, buy a halfnut.

Or buy one of each :)

Edited: 20 July 2006, 8:54 p.m.


#14

I have one of each.

Sometimes you feel like a Fullnut. Sometimes you don't :-)


#15

I sold a blank nut, half nut 41CX to W. A. C. Mier-Jedrzejowicz with a missing cover piece for the program and user key. He told me that I actually sold him a quarter nut.


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