41C Halfnut

[KimH]

On TAS I bought myself a “for parts” & “not working” half-nut 41c…

Mainly because I could see the serial and it looked pristine.. could this be real or a frankencalc? Does such a thing even exist? 41C half-nut..?

Serial 1940A02255 looks as stamped from the factory, not dodgy, not altered

When it arrived I was suspicious, as one would be.

It is mint, nothing suspicious at all, the bezel is silver as it should be. The badge sit perfect and show - also in silver - what it should.. interesting

So, can I turn it on, is it something simple like “droopy batteries”

Well, it didn’t turn on,

in with my 82120D that should wake it up, if anything will.

Nope,

So does it get power or has it been smashed by 4 of the 12 volts cells, you know what I mean.

In with the “lightsabre” pressed the switch - nope, no reaction.

Opened up, all halfnut inside. Looked fine

Swapped the battery/port thingy - maybe it is a soggy rubberband under the contacts

Yesss - It works. That was it

GTO . . And I get 046, looks right, 2 of the 106A modules in and SIZE 010 - all good 00 REG 181.

A fine addition to my stack of 41 models

So, here is the question I could/cannot find the answer for. Did HP after the cost optimized Half-Nut actually make 41C versions as replacement-parts? Or is this something else?

Where does the 64 registers of memory reside - is it in the single chip or hidden in the display? Or better, is there a trick to enable the rest of the memory to a CV (not that I would do that - it is good and interesting as it is) - I doubt they actually made 2 versions of the product. The C with 64 and CX with 320 registers. Does anyone know the answer?

[Raymond Del Tondo]

(10-12-2024 02:28 PM)KimH Wrote:  So, here is the question I could/cannot find the answer for. Did HP after the cost optimized Half-Nut actually make 41C versions as replacement-parts?

Yes:-)

IIRC the basic halfnut is a C,
with the quadratic chip onboard it's a CV,
and with the bridge board a CX.
However I could be wrong here, so this has to be checked.

[KimH]

(10-12-2024 04:25 PM)Raymond Del Tondo Wrote:  

(10-12-2024 02:28 PM)KimH Wrote:  So, here is the question I could/cannot find the answer for. Did HP after the cost optimized Half-Nut actually make 41C versions as replacement-parts?

Yes:-)

IIRC the basic halfnut is a C,
with the quadratic chip onboard it's a CV,
and with the bridge board a CX.
However I could be wrong here, so this has to be checked.

Thanks Raymond!

The quadratic chip is there, it has to be - it’s the CPU (and maybe more) the display is very different from the Coconut and that is why I suspect the memory is in that part. And yes, the bridge makes it a CX. Let’s see…

I am curious what reaction there will be on the serial - it is VERY low and I anticipate some energy release on that topic alone - chuckles…

Kim

[aurelio]

(10-12-2024 05:24 PM)KimH Wrote:  

(10-12-2024 04:25 PM)Raymond Del Tondo Wrote:  Yes:-)

IIRC the basic halfnut is a C,
with the quadratic chip onboard it's a CV,
and with the bridge board a CX.
However I could be wrong here, so this has to be checked.

Thanks Raymond!

The quadratic chip is there, it has to be - it’s the CPU (and maybe more) the display is very different from the Coconut and that is why I suspect the memory is in that part. And yes, the bridge makes it a CX. Let’s see…

I am curious what reaction there will be on the serial - it is VERY low and I anticipate some energy release on that topic alone - chuckles…

Kim

Hi KimH, do you have pics of this calculator? I'm very curious and they could sure help in understanding

[Raymond Del Tondo]

(10-12-2024 05:24 PM)KimH Wrote:  The quadratic chip is there, it has to be - it’s the CPU (and maybe more)

Thanks for the correction:-)
Then maybe a solder bridge could indicate C or CV?

[aurelio]

(10-12-2024 08:34 PM)aurelio Wrote:  

(10-12-2024 05:24 PM)KimH Wrote:  Thanks Raymond!

The quadratic chip is there, it has to be - it’s the CPU (and maybe more) the display is very different from the Coconut and that is why I suspect the memory is in that part. And yes, the bridge makes it a CX. Let’s see…

I am curious what reaction there will be on the serial - it is VERY low and I anticipate some energy release on that topic alone - chuckles…

Kim

Hi KimH, do you have pics of this calculator? I'm very curious and they could sure help in understanding

???

[KimH]

Regarding images, I'll load some once back home - right now Dubai heat is what I have to fight.

So now I am back home and have taken some Pictures - hope they are not too small - I am limited in file size..

I found an older YouTube from our Friend in Australia EEVblog - Halfnut Teardown which has some interesting references as it is a Halfnut CV

My CPU is 1LF5-0303 from 85181 and his is 1LM2-0002 87441

You can also compare the Display "chip"
- Mine is 5061-7273 - 8524
- His is 5061-7255 - 8747

I have read somewhere - can't recall where - that they where developing a 100k chip which should hold the ROMs.

I wish I had the tools to check the ROM version... but I don't

[aurelio]

(10-17-2024 06:14 AM)KimH Wrote:  Regarding images, I'll load some once back home - right now Dubai heat is what I have to fight

Thank-you KimH

[Andreas Debus]

The real question is .. would you sell a 41C or CV to a mere mortal who longs for one since his school days (1972 to 1985) .. and went for a CASIO FX-602P instead?

[KimH]

(10-17-2024 10:15 PM)Andreas Debus Wrote:  The real question is .. would you sell a 41C or CV to a mere mortal who longs for one since his school days (1972 to 1985) .. and went for a CASIO FX-602P instead?

Well, you'd have to go on the same Journey that I did/had - like this starterkit Auction - 10 hours to go

[aurelio]

(10-18-2024 06:10 AM)KimH Wrote:  

(10-17-2024 10:15 PM)Andreas Debus Wrote:  The real question is .. would you sell a 41C or CV to a mere mortal who longs for one since his school days (1972 to 1985) .. and went for a CASIO FX-602P instead?

Well, you'd have to go on the same Journey that I did/had - like this starterkit Auction - 10 hours to go

Since a lot of time I don't surf on ebay, but....
the final price I think means a good purchase, if you think that the buyer got a working (and clean, it seems) 41c tall key, a couple of modules, the pouch and the card reader!!
Even if the card reader needs maitnenance anyway a good shot, I think!!

[KimH]

Added some images in previous post

[aurelio]

Thank-you KimH, it looks like another beauty

have a glance here , please

[Raymond Del Tondo]

Hi Aurelio,

thanks for the link.

I think I found a possible place which decides if it's a C or CV.
If you compare Kim's pic of the CPU and yours,
then you'll notice two solder bridges in the lower right of the CPU on your pic.

The main board base number is the same, the revision different,
and the CPU chip has a different number.

I don't have a halfnut CV handy, but could it be possible that the
1LM2-0002 can be configured to be a C or CV by these solder bridges?

[aurelio]

(10-20-2024 08:37 PM)Raymond Del Tondo Wrote:  Hi Aurelio,

thanks for the link.

I think I found a possible place which decides if it's a C or CV.
If you compare Kim's pic of the CPU and yours,
then you'll notice two solder bridges in the lower right of the CPU on your pic.

The main board base number is the same, the revision different,
and the CPU chip has a different number.

I don't have a halfnut CV handy, but could it be possible that the
1LM2-0002 can be configured to be a C or CV by these solder bridges?

Hi Ray, I see what you described, it could be, but also I don't have a halfnut CV to open and check, sorry

[KimH]

(10-20-2024 07:41 PM)aurelio Wrote:  Thank-you KimH, it looks like another beauty

have a glance here , please

Thanks for that link Aurelio, one more part for the story!

I suspect the cpu-chip determines whether it is a C or CV - my board does not have the pads and CVs appear to have them. Well, someone will know…

[aurelio]

(10-20-2024 09:09 PM)aurelio Wrote:  

(10-20-2024 08:37 PM)Raymond Del Tondo Wrote:  Hi Aurelio,

thanks for the link.

I think I found a possible place which decides if it's a C or CV.
If you compare Kim's pic of the CPU and yours,
then you'll notice two solder bridges in the lower right of the CPU on your pic.

The main board base number is the same, the revision different,
and the CPU chip has a different number.

I don't have a halfnut CV handy, but could it be possible that the
1LM2-0002 can be configured to be a C or CV by these solder bridges?

Hi Ray, I see what you described, it could be, but also I don't have a halfnut CV to open and check, sorry

Hi Ray, I forgot that for the comparison between the two boards, I had posted a link with pics from the Diego's site, on the old thread that could be useful to apreciate the differencehere.