After my two fauxpas; re the HP41C below, here is the book


so far.

I should never type without reference material. To clarify ;-) the HP41C card reader does indeed have fewer nylon balls then the HP 65, 67, and topcats, if you deem zero balls fewer! Also the cam is eccentric.

In any case these two facts were correctly stated in the 'book', if only I had referenced my chapter 8!!!

Still some chapters left to do, including the HP19C or 10 chapter. I still have to aquire some examples for restoration photos of these two as I have all the others required. In fact if anyone out there has a defunct 19C that requires repair I will do it for free (if possible) just to have an example for the book. Let me know if you have a donor that I can repair for documentation and then ship back to you!

Now to the posting, here are some shots of the book as it appears now.

The Cover:


Page 16 refering to the HP 65 restoration:

Again the HP65 (Classic chapter) and some card reader tips:

Chapter 6, the HP 01 cricket:

Second section of Chapter 8, the Fullnut:

HP 41C the third section of Chapter 8, the card reader:

Stuff I should have refered to before typing responses on the HP41C card reader below!!

One of the appendices, this one will include diagnostic programs documentation for those calculators that do not have built in diagnostics:

I have selected a large clear Verdana font. All the figures are referenced in the text with large clear labels where required. The book as you can see is spiral bound, 11 inches by 8.5 with clear large figures with excellent resolution.

When done (HCC2010 or before) it will be aproximately 300 pages with over 400 illustrations. It will be peer reviewed also and will probably be completed with online publishing and some hard copies available through me. Have yet to pin all that down.

The current version illustrated here (just to see how it would look and to see how the photos would print) still requires 3 chapters to be completed and as a one off print at the local STAPLES it cost me $80 (200 pages bound in high res. colour laser). This will come down once I have established costs with a publisher.

Cheers, Geoff in rainy busy Olympic Vancouver.

Edited: 26 Feb 2010, 6:16 p.m. after one or more responses were posted


Geoff, awesome, can't wait to get one, preferably signed by the author :-) BTW - I do have a 10c which could use some restoration if you are in need for an example there as well. The other thing should be on its way to you by tomorrow morning in either case.





thanks for the offer but I did a typo on the request, it is the printing HP10 or printing 19C that I require. In fact the 10C voyager is the subject of one section of the Voyager chapter.

If you have a printing 10 (STING Family) that would help!

I will keep an eye for the other thing in the mail.

Cheers, Geoff


This is really a stunning piece of work, Geoff. Thank you, in advance!



Cheers, Geoff in rainy busy Olympic Vancouver.

Lucky you!

This looks fabulous, Geoff. Forgive me if I missed this in earlier threads, but will it include upgrades (e.g 42s memory), or just restoration and related repairs?



I am trying to make it as comprehensive as possible. The HP 42S is the subject in the Pioneer section and includes the memory upgrade as well as mentioning the clock speed. There will also be a section on the Stretch Pioneer featuring an HP48SX.

See below about the pioneer chapter.

Cheers, Geoff

Edited: 26 Feb 2010, 7:21 p.m. after one or more responses were posted


There will also be a section on the Stretch Pioneer featuring an HP48SX.

Yes! Thanks! (Although I've never heard that term before, "stretch Pioneer", I like it. I once said the 48SX looks like a "Pioneer on steroids").


Also known as the Charlemagnes. I have been using the terminology for naming the families following "A Guide to HP Handheld Calculators and Computers" by W.A.C. Mier-Jerzejowicz.

Wlodek has been helping me with suggestions and examples to restore as well. All that will be mentioned in the book.

Of course, every one or two months and another repair comes to light. For example I had no idea about the radix jumper in the spice so of course I have to include the radix change with examples in the Spice chapter.

Other things come up such as 42S low contrast problem involving jumper switch and a different capacitor show up and have to be included. Of course this entails actually doing the upgrade and then modifying the chapter.

The problem is YOU people keep comming up with new clever ideas that have to be included!

Cheers, Geoff


Geoff, it looks like an excellent piece of work, I think you will have sales to many forum members, including me.

The problem is YOU people keep comming up with new clever ideas that have to be included!

That's what updated editions are for :-)



Great :-).

Small typesetting problem: Captions (first line of it) should be on the text body baseline. You did it in Word, right? ;^)

You will immediately see an improvement, when you try to adjust it, even by hand, if Word still doesn't support baseline snaps.


In Microsoft Publisher,

In fact these photos are slightly out of date as typos, typsetting and some other small glitches have been solved.

keep pointing them out thought, and I am sure the peer review team will not be merciful ;-)

Cheers, Geoff


Ok, another thing: When defining a paragraph style, never allow for a page break right after the first or before the last line of a paragraph, so you never have just one line of it on a page.

You probably fixed that already.



Keep going


Problem is when I move or change or resize a figure it ricochets down the chapter. Each chapter is it's own section in Publisher. this limits how much damage I can do when I change something at the beginning of the chapter.

New to this aspect. My thesis and journal articles follow a preset published set of rules. Apparently I can follow those! This ad-hoc approach has its own rewards though.

Once all the text is completed and the figures done positioned correctly I will go through the pages and clean up the stray sentences and etc...


Edited: 26 Feb 2010, 6:57 p.m. after one or more responses were posted


Awesome work, Geoff! Any way of twisting Hp's arms to buy this book in huge quantities to reduce the selling price? :-)

l will definitely be placing an order from you .


Actually working on that aspect!

Cheers, Geoff

and thanks for the compliments.



You book looks fantastic! I'm looking forward to it as I have a couple of 41CX keyboards that need a little attention and I have two extended memory modules that I would like to merge together. I also just got an HP-55 that needs a little restoration as well as a second 71b whose battery terminals need some work.

It's great to see the section on rebuilding the 41 card reader. Do you intend to include other 41 peripherals in a second volume, perhaps later on? It could cover the 143/162 peripheral printers as well as the 161A tape drive and the 9114 A/B floppy drives. For instance, I have a 41 barcode wand in which the threaded ring the tip screws into has broken apart so the tip is hanging on by a small thread. It would be interesting to see how to fix that.

I will be purchasing a copy of your book when it's released. Thanks for doing this for all of us. We appreciate it.



In fact I have section in the appendix for memory module combination "double x-memory". Restoring different battery packs.

The HP41 peripheral section could be a book on its own. So other than the card reader, calculators, memory upgrades, battery packs and a few other sections such as heat stake replacement/repairs, I think the peripherals will have to wait.

Take a look a Mathias site for the number of HP41 peripherals there are!!

I will be restoring a GEODAT 126 in the appendix which may help people get into other types.

Yep, THAT book would easily be 500 pages on its own!!

So far the logistics entails finding a representative of each family, some peripherals, memory upgrades and etc and then actually doing/documenting each repair.

Peripherals would be fun and I do have the following HP41 peripheral which could be included but I think the calculators will be the focus for HCC2010:

HPIL printer
HPIL plotter
Non HPIL printer
Infared printer
HPIL tape drive
HPIL floppy drive
LASER wand
6 card readers

As it is I have included and completed the following restorations and upgrades:

HP65 complete restoration
HP45 quartz crystal upgrade
HP55 quartz crystal replacement
Classic series LED block replacement as an example of unsoldering.

HP29C complete restoration
Woodstock battery modifications

HP97 complete restoration including card reader and printer

HP01 complete restoration including case, quartz crystal, trimming
capacitor and possible an LED block swap

HP34C soldered complete restoration
HP spice unsoldered complete restoration

HP41CX complete restoration, with Diego Diazs battery pcb included
HP41CV complete restoration
HP41C early version complete restoration
Card reader with it's own section complete restoration
Double ex memory section

HP10C complete restoration including aluminum bezel swap
HP11C complete restoration including heat stake removal and

71B early version complete restoration
71B later version complete restoration

HP18C complete restoration
HP28C complete restoration

HP42S complete restoration, memory upgrade, contrast enhancement
HP48SX complete restoration

battery pack reconditioning for CLASSIC/Topcat, Woodstock, Coconut

battery pack substitute for classics with bad contacts
battery pack repair for broken spice with bad ribbons

make your own drying box

make your own overlays

make your own rubber feet

Discussion on ESD protection while working on calcs

Diagnostic programmes


references, citations and credits (including URLs with permission)

EYE CANDY photos of before and after (playboy section for calc nerds)


As you can see a lot of work and photography. I think peripherals not covered would indeed fit in a book on its own. Having said that, the title is HP Calculators (with some extras).

My wife is renovating the house, I am restoring my 1973 Celica from the ground up, work and the book so pretty busy here for the time being. Company just called and now off to Hong Kong tomorrow.

Work, work, work!!! Of course during my first 3 hour break I will work on the book on my laptop.

Cheers, all!

Edited: 26 Feb 2010, 9:08 p.m.


Super! I want one when it's ready.

Since you can still edit it, a quick search-and-replace of "fullnut" replaced with "coconut" would be good. The original HP-41's were "coconuts." HP never had a "fullnut."


Thanks Garth and actually corrected. I was using a general user term but have switched to HP terms whenever they exist in the latest version. This book was produce about 7 months ago to see how the graphics and text read and as such does contain errors. No doubt the final edition will also contain errors! I haven't submitted the final copy to the peer review group (I think it may compose of the HCC committee members, fingers crossed as they are busy people!).

Codenames such as the 'Coconut HP41C', 'Silverbird Hp41CV' and 'Honeynut HP41CX' are used in the book. The 41CX was the Honeynut and later came with a simplified electronics and was codenamed 'Halfnut' refering to the size of the PCA. In fact, according to Wlodeks book, it may have refered to the fact that the HP41 newest design was to include only two ports instead of four. The user group has developed the term 'fullnut' although it is not an HP codename to differentiate between the original versus halfnut electronics.

Cheers, Geoff

"A Guide to HP Handheld Calculators and Computers" by W.A.C. Mier-Jerzejowicz

Edited: 26 Feb 2010, 7:18 p.m.


Thomas Radkes observations on the typos and text position errors in the posting above ;-)

Firstly, choose a Reference calculator that exhibits most of the restoration points of interest and represents the majority of the family.

For example, in the Pioneer family all the calculators can be accessed the same way. Once inside the 42S lends itself to upgrading, both memory (jumper change and memory chip), clock speed (quartz crystal) and contrast (by swapping a capacitor and changing a jumper). That is, once inside to repair the standard problems, keyboard, zebra strip contact foam, keys and etc this example allows for upgrades.

Document each step by taking a raw series of photos with a macro lens, lighting and appropriate background. Pick the best photo and crop, label, align and size for correct use as a figure.

Place the figures in the appropriate order on the virtual book and then write the text around the sequence of figures.

Go back and take new pictures, insert them after cleaning them up and write more text. I try to over do the pictures as they are worth a thousand words.

Here are some shots of the Pioneer chapter with a reference calculator. Notice the reference calculator is the HP42S. The differences section of the Pioneer chapter includes the Stretch Pioneer (Charlemagne). I included the Stretch Pioneer in with the Pioneers as their construction is extremely similar.

The following pages show the figures cropped and sized but not yet labelled. The labelling will depend on the text.

This is the reference section and you can see some of the labels have been applied to the photos.

The next step is to write the text step by step referencing the figures. This of course changes the location of each figure with respect to the page number.

Once completed then correct any stray sentences and add or change some of the figures for better explanatory clarity.

Cheers, Geoff and it still raining!


Hi Geoff,

I've been amazed by your outstanding achievements for a long time, Well I'm afraid my English isn't fluent enough to say it.

...and I'm also afraid you'll have another copy of your book to send to Europe when it'll be finished :-)

I wish you great success !

Greetings from France,


In any case these two facts were correctly stated in the 'book', if only I had referenced my chapter 8!!!

If all else the manual - even if you wrote it yourself :-)))

We're all looking forward to it's imminent release.




Amazaing, great job Geoff!


Hi Geoff, Excellent work! Waiting for the release. Best regards, Prabhu Bhooplapur


Amazing. Me want


Looks absolutly fantastic. I want that book!


You will have to ship more than one copy to Europe! :)


Congrats, Geoff!


Luiz (Brazil)


What more could a calculator geek, in rainy Vancouver, want besides a great book on a wonderful topic ??


I go I would like to thank everyone for their support, comments and ideas as well as emails.

On another note, I have a donor hp 19C that needs repair that I can use. Of course if anyone has an extra messed up one that they want to sell, I am always willing to purchase it.

Cheers, until next week, Geoff


Hit the electronic stores in the back streets and look for the one with dusty boxes in the front window.

Can't photo the find here but I can describe it. It cost $20 Canadian dollars. A brand new in box (dusty) 38G still shrink wrapped complete with manual.

The box has a copyright of 1995 and the serial number of the calculator is 3539sxxxxxx.

Now to find the shop with the 23 HP42S in the back room still shrink wrapped. They might be here as this 38G is 1995 vintage. Now that would be fun to find.

Cheers, from foggy misty Hong Kong.

What a hockey game!!!! Even if the anouncers were speaking chinese, incredible hockey (Canada vs USA).



Even though I personally like the 38G, the market does not. A brand new old stock 38G is worth about what you paid for it.

Keep looking for the 42S cache.


Hi Geoff,

Your work on this book looks as outstanding as the restorations described inthere.

My sincere congrats on that... ;-)

I will still take a few weeks to get back to Europe, but I'd like to renew my interest in getting one copy when you release the final edition.

Best wishes.



I have a partially working HP 10 that I tried to restore. I cleaned the circuit boards, etc. and it still isn't working right... several numbers don't work (not the keyboard) and it won't print, etc. Let me know if you want to borrow it.

I spent a fortune on two of them, combining the best parts, so I do have a working one. Definitely the most I've ever spent on a model, but it was necessary....


It looks like an instant classic, Geoff.


Congratulations ! It looks fantastic, be prepared to send some copies to Italy as well ! cheers, Alberto

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