How can I have a HP-41CL?
The possibility of having new production?
I entered the site and the author made ​​it clear that one of 41CL stayed with him.
This indicates that not going to produce?
I appreciate any information

Edited: 4 July 2011, 4:10 p.m.


The first batch is out (approx. 20 units) and are beeing thoroughly tested

These beta units are absolutely great and as soon as the testing has finished there might start a production of the next batch (Alpha units?!)

To get more informations check:


or send an email to:

Monte Dalrymple


Hope this helps


Have to concur with Roger,

The HP 41CL is much more then advertised. Unbelievable power at your finger tips.

Just for example, faster, I mean fast. Recoverable state in case of MEMORY LOSS or loss of power. Recoverable in the sense that you can copy your entire calculator to USER FLASH RAM which is writable; 'YFRM' to FLASH and copy-able; 'YMCPY' from FLASH.

No need for card reader, cassette, disc drive back up. In fact I now have two calculator states resident in flash. A suite of programs taking up 250 program registers and 200 x-memory registers stored in a FLASH RAM address belonging to my Palynology studies. And a suite of programs with aviation related programs and x-memory.

The following information relates to the creation of the FLASH RAM files and the copy back. No need to understand the commands as you will learn them and they are part of the CL functions which get plugged into PORT 1 Lower (PLUG1L).

Sequence of steps to create the write from 800 to OC9 and 804 to OCF:

1. TURBO50
2. "062>812"
4. “812-RAM” YFNS in RAM so YFWR can be used.
6. “800>0C9
8. “804>OCF
10. “YFNS”
11. PLUG1l

The above inputs can be automated in the form of a program!

Now at a complete “MEMORY LOSS” state:

1. MMUCLR basic reboot steps to enable MMU etc.
2. “YFNS”
5. TURBO50
6. “0C9>800” copy calc state from FLASH back to 800
7. YMCPY and 804.
8. “0CF>804”
10. XEQ “PG” see below
11. XEQ “SGMT” see below

1. LBL PG my suite of standard modules
2. “YFNS”
4. “CCDX”
6. “PPCM”
7. PLUG2
8. RTN

1. LBL SGMT my clock is set to GMT (+7) hours for
2. TURBO50 labelling. Programs with date and for
3. DATE the world time program with city airport
4. PROMPT identifiers.
5. SETDATE The need for this routine is during a power
6. TIME? loss or MEMORY LOSS the time module has a
7. PROMPT power interupt and as such needs a reset.
9. "+-GMT" The CL in TURBO50 is so fast that the
10. PROMPT SETIME function occurs when you hit R/S
11. T+X
12. CLA
13. TIME
16. END

To switch to another state:

ON+CLR and follow the MEMORY LOSS state example but substitute the calculator state memory address that you now require. As you can see it is no leap to run some programs, collect the data, store the data in FLASH and then switch calculator states and run programs for other reasons, switch back and continue with the previous state.

Well you get the picture, everything creates more ideas and the emails between the Beta testers includes creating ROMS, which would substitute the need for a backup state, unless you have data involved to serial communications with import and export functions to, well check out the link Roger posted.

I think with WP34S and HP 41CL this is an extremely interesting year. I forsee, with the availability of the CL the prices for used 41C, CV and CXs going up!

Cheers, Geoff

I have barely scratched the surface of the CL capabilities!


Edited: 6 July 2011, 2:52 p.m. after one or more responses were posted


HP-41CL is fantastic, wonderful, etc..
But will he stay in the hands of only 21 people? :-(
Now I know what I felt when I showed my friends my HP-41CY.
I'm paying for my sins.
I want an HP-41CL.
Geoff has no heart you doing all this suffering had to be banned here,;-).


The beta testers are still working out the best ways to copy things to ram and flash ram, as well as loading new .rom images into the 41CL.

The procedures to write to flash are very dangerous is you do not know what you are doing OR if you make a mistake. Think how things were with the early synthetic programmers investigating register c and then increase the risks. :-)

that said, Monte had people sign up to buy HP 41CL units but when the time came, quite a few of the original 20 never responded to his email about wanting a 41CL.

That may lead Monte to the (hopefully wrong) conclusion that people **say** they want a 41CL board but when the time comes, who will pay for it?

Monte may be forced to have a pay-in-advance model with the next batch (which I think won't happen until the beta testing process winds down a bit).


As Gene says, have to be careful with copying to FLASH RAM. The locations chosen have involved a LOT of reading, EMAILING and confirmations.

I posted them to show you what the CL can do and its potential. After all this is Beta testing. So those of you without a CL board don't do this ;-)

Those of you with a beta CL board, READ the MANUAL!

Enough of the serious stuff now.

Gene is correct, for Monte not to show a deficit, those that want one must follow through!

Cheers, Geoff

My four phases of 41C life:

my first 41C                1980
my foray into synthetics 1982
my first 41CX 1984
my first 41CL 2011

31 years later and the 41 (CL) is a 21st century machine!


Edited: 5 July 2011, 4:26 p.m.


Gene / Geoff:

I wondered where you lot had gotten to! Thanks for the dispatch from the front.

If one of you 41CL-o-nauts could post a similar report occasionally it would make very interesting reading for those of us following along at home.

(I read Monte's article in Circuit Cellar and was amazed at what he's accomplished.)






what with the wp34S, the book, the CL, the car... who has time to eat!

Anyone, and I mean ANYONE, who enjoyed the HP 41 in the past will love this machine.

this is even beats the SNIPE known as the "43S".

Cheers again.



Where did you see a "43S" ?

Looking forward to your book - hope Marcus can get some specimens in San Diego :-)



Walter; Have you never asked for or been asked for a metric crescent wrench? Don't Europeans hunt for the wiley Snipe?

If not, look up snipe hunt on wikipedia.

Joerg is gonna love this one. He thought we were crazy before...


DB got it in one!

Hunting the Snipe, that elusive bird! Sort of like a wild goose chase?

Great science fiction series starting with an alien aloof survey of the planets with technology. The alien was called a snipe because the astronomers had been looking for so long and not found extraterrestrial life. Can't remember the series though or the author: Baxter?


Edited: 6 July 2011, 2:22 a.m.


I wondered where you lot had gotten to! Thanks for the dispatch from the front.

Yes, we're all heads-down trying to absorb the new machine's capabilities and (literally) studying its marvels. It's a wondrous accomplishment, way better than the most optimistic expectations... and yet best.

Back to study!


Angel is correct, emails flying, never so much fun since sythetics came about for the C.

Just to show how easy a full copy of the entire calculator state can be I converted the manually input sequence of keys in the first post to a program. The program copies the key assignments, memory registers, program registers, extended memory, flag status... well you get the idea. Similar to a WRTA or WALL command but with the added bonus of carrying all extended memory along with it!

Calculator to Flash "YCTOF"

002 TURBO50
003 "062>812"
005 "812-RAM"
006 PLUG1L
007 "0C9000"
009 "800>0C9"
010 YFWR
011 "804>0CF"
012 YFWR
013 "YFNS"
014 PLUG1L
015 END

I have run the above program and it functions correctly. It takes 44 seconds to run in TURBO50 mode. You can see at that there is a copy command to RAM (YMCPY) and two copy commands to FLASH (YFWR)which explains the time lag.

When a MEMORY LOSS ocurrs for various reasons like 0 STO C ;-) for you synthetic nuts or power interupt or conflict between the ROMS (all things which afflicted the 41C for a novice or pro). You have a safe image which can be restored in about 25 seconds with the following manual key inputs.

2 "YFNS"
5 "0C9>800"
7 "OCF>804"

Of course, READ the manual if you are lucky enough to get one of these! Genes caveat is absolute, messing with FLASH can be dangerous and relies on explicit knowledge of memory addresses, all supplied in Montes great CL manual:

HP 41CL manual


Edited: 6 July 2011, 3:16 p.m.


...You have a safe image which can be restored in about 25 seconds with the following manual key inputs.

2 "YFNS"

That's a really, really cool (and two decade overdue) capability.

The restore listing should get added to the to the "41CL" label sticker sheet, in a size that would fit the indent in the battery pack.


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