If I were to buy an LED model...
11-09-2019, 01:40 AM
Post: #1
 Dave Britten Senior Member Posts: 1,179 Joined: Dec 2013
If I were to buy an LED model...
Right now the oldest HP I have is my 41CV, but I've been entertaining the idea of buying an older LED model just for kicks. I'm looking for recommendations on which would be the best to look out for in terms of affordability, durability, and ease of fitting modern batteries (like a couple AA Eneloops).

I don't have an attachment to any particular model, since they're all a little before my time, and I find scientific and financial models equally appealing. I would like something programmable - even the basic capabilities of the 25 would do just fine - though the jack-of-all-trades 27 does intrigue me too.

I don't feel any need to pay top-dollar for a card reader or printing model and get it working, but if one fell into my lap really cheap, I wouldn't say no of course.

My suspicion is that the 38E/C or 33E/C would be the two closest matches that wouldn't cost hundreds, but if there's a better option, I'm all ears.
Post: #2
 Michael de Estrada Senior Member Posts: 337 Joined: Dec 2013
RE: If I were to buy an LED model...
Hi Dave,

You will have a hard time finding either a Woodstock such as the HP 27 or a Spice such as the HP 33c in good working condition. If you do, you will have to pay a king’s ransom for it, especially a Woodstock. The Classics such as the HP 55 were bulletproof, and there still are many to be found in good working order for a reasonable price. If you are willing to dispense with programming, you can easily find a clean HP 45 in good working order for under $100. Also, you can power the non-cardreader Classics directly from the AC adapter without a battery installed, whereas you cannot do this with a Woodstock or Spice. Michael 11-09-2019, 11:07 AM (This post was last modified: 11-09-2019 11:53 AM by Maximilian Hohmann.) Post: #3  Maximilian Hohmann Senior Member Posts: 614 Joined: Dec 2013 RE: If I were to buy an LED model... Hello! The cheapest LED model is probably the HP-45. They are in plentiful supply and it is still possible to find them here (in Europe) for 30 Euros or less. Maybe not in perfect cosmetic condition, but they all work. I have yet to see a non-working HP-45. Mark Hoskins will sell you a battery pack with more modern batteries than the original ones which can still be charged with the original charger but will last for many hours. Unfortunately the HP-45 is a little boring and not able to do much. My personal candidate for an LED model - if I could have only one - would be an HP-25. That one is _the_ Woodstock calculator. It came out early, yet is programmable. The "smarter" successors (25C, 27, 29) came later, or rather too late to be produced in large numbers, and fetch crazy prices on the market which they are not worth. For a collector maybe, but not for someone who just wants an HP calculator with LEDs. A working 25 can, with patience and luck, be found for less than 100 Euros here. Or you buy a non-working one cheap and put one of PANAMATIK's low-power boards inside. But this is no low-cost solution... And if you want the ultimate LED calculator from HP you need to look for an HP-67. That one is the latest (and best - or at least equal to the Ti59) LED calculator ever designed. But they have become rare and rather expensive and usually require some maintenance (card reader) before they can be used. Regards Max 11-09-2019, 11:42 AM Post: #4  Massimo Gnerucci Senior Member Posts: 1,789 Joined: Dec 2013 RE: If I were to buy an LED model... (11-09-2019 11:07 AM)Maximilian Hohmann Wrote: And if you want the ultimate LED calculator from HP you beed to look for an HP-67. That one is the latest (and best - or at least equal to the Ti59) LED calculator ever designed. Or, maybe, a 34C. No card reader problems, no unbearable labels under the keys. Greetings, Massimo -+×÷ ↔ left is right and right is wrong 11-09-2019, 11:59 AM Post: #5  Maximilian Hohmann Senior Member Posts: 614 Joined: Dec 2013 RE: If I were to buy an LED model... Hello! (11-09-2019 11:42 AM)Massimo Gnerucci Wrote: Or, maybe, a 34C. No card reader problems, no unbearable labels under the keys. If you can find one at all... And eben if, it will suffer from cheap cracked plastic and battery leakage. Personally I vastly prefer the labels on the wrong side of the keys over that! One could of cause also look for an HP-65. For some reason they are easier to find (and also cheaper) than an HP-34 or 67. And it is a real piece of history, the first prgrammable scientific pocket calculator. Built to last. Replace the O-rings in the card reader, get a replacement battery pack and you are good to go for another 50 years. Regards Max 11-09-2019, 12:19 PM (This post was last modified: 11-09-2019 12:20 PM by Massimo Gnerucci.) Post: #6  Massimo Gnerucci Senior Member Posts: 1,789 Joined: Dec 2013 RE: If I were to buy an LED model... (11-09-2019 11:59 AM)Maximilian Hohmann Wrote: Hello! (11-09-2019 11:42 AM)Massimo Gnerucci Wrote: Or, maybe, a 34C. No card reader problems, no unbearable labels under the keys. If you can find one at all... And eben if, it will suffer from cheap cracked plastic and battery leakage. Personally I vastly prefer the labels on the wrong side of the keys over that! One could of cause also look for an HP-65. For some reason they are easier to find (and also cheaper) than an HP-34 or 67. And it is a real piece of history, the first prgrammable scientific pocket calculator. Built to last. Replace the O-rings in the card reader, get a replacement battery pack and you are good to go for another 50 years. Regards Max You are right, of course, but my point was that the 67 was not the latest LED calculator ever designed. And the 34C is quite powerful, too. Greetings, Massimo -+×÷ ↔ left is right and right is wrong 11-09-2019, 12:44 PM Post: #7  Maximilian Hohmann Senior Member Posts: 614 Joined: Dec 2013 RE: If I were to buy an LED model... Hello! (11-09-2019 12:19 PM)Massimo Gnerucci Wrote: You are right, of course, but my point was that the 67 was not the latest LED calculator ever designed. And the 34C is quite powerful, too. That's right of course. I tend to forget aout the "Spice" series. This because I only have them for collecting purposes and never saw one being used in real life. Back in 1978 other manufacturers already made more powerful and yet cheaper calculators, e.g. the Casio 501P with mass storage access (cassette tape interface) and seemingly indefinite battery life compared to these Spices. Regards Max 11-09-2019, 01:35 PM Post: #8  Dave Britten Senior Member Posts: 1,179 Joined: Dec 2013 RE: If I were to buy an LED model... Thanks for all the tips! I didn't realize the classics could be safely used without a battery, so that's an important point to consider. The 55 looks like it's way out of my price range, so that would narrow it down to the 45 or 80, or possibly 70. I'd probably lean toward the 80, since it has the distinction of being the first financial calculator. Are the Spice models especially troublesome to keep working? It seems like a working 38C/E can be had for under$100, but I wouldn't want it to turn into a money pit/time sink.
11-09-2019, 01:44 PM
Post: #9
 Massimo Gnerucci Senior Member Posts: 1,789 Joined: Dec 2013
RE: If I were to buy an LED model...
(11-09-2019 01:35 PM)Dave Britten Wrote:  The 55 looks like it's way out of my price range, so that would narrow it down to the 45 or 80, or possibly 70.

Yeah, that one! ;)

Greetings,
Massimo

-+×÷ ↔ left is right and right is wrong
11-09-2019, 02:29 PM
Post: #10
 Michael de Estrada Senior Member Posts: 337 Joined: Dec 2013
RE: If I were to buy an LED model...
(11-09-2019 01:35 PM)Dave Britten Wrote:  Are the Spice models especially troublesome to keep working? It seems like a working 38C/E can be had for under $100, but I wouldn't want it to turn into a money pit/time sink. The Spices are flimsy and tend to fall apart, but if you are very gentle with them they will continue to work. Many of them have corroded circuit board lands and/or broken battery contacts, so they can’t be charged or run off batteries. The first generation Spices used a stupid unsoldered construction that relies on the IC chips, control board and LED array being tightly clamped together. Over time parts get loose and you start losing segments in the LED display and random error messages. The cases crack, the keyboards develop bad keys and and the On/Off switch becomes flakey. I am constantly having to open mine to replace parts pirated from other non-working Spices, so they are definitely high maintenance. The Spices were a failed attempt by HP to match pricing of competitors such as TI, by making them cheaply, and it almost destroyed their reputation for producing premium quality calculators. They returned to their senses with the Voyagers, which are the highest quality and most durable calculators HP ever made. 11-09-2019, 02:30 PM Post: #11  Dave Britten Senior Member Posts: 1,179 Joined: Dec 2013 RE: If I were to buy an LED model... (11-09-2019 01:44 PM)Massimo Gnerucci Wrote: (11-09-2019 01:35 PM)Dave Britten Wrote: The 55 looks like it's way out of my price range, so that would narrow it down to the 45 or 80, or possibly 70. Yeah, that one! Wasn't quite sure what your comment meant, but after seeing the going rates for this low-end financial model, I think that narrows it down further to the 45 or 80. 11-09-2019, 02:39 PM Post: #12  Dave Britten Senior Member Posts: 1,179 Joined: Dec 2013 RE: If I were to buy an LED model... (11-09-2019 02:29 PM)Michael de Estrada Wrote: (11-09-2019 01:35 PM)Dave Britten Wrote: Are the Spice models especially troublesome to keep working? It seems like a working 38C/E can be had for under$100, but I wouldn't want it to turn into a money pit/time sink.

The Spices are flimsy and tend to fall apart, but if you are very gentle with them they will continue to work. Many of them have corroded circuit board lands and/or broken battery contacts, so they can’t be charged or run off batteries. The first generation Spices used a stupid unsoldered construction that relies on the IC chips, control board and LED array being tightly clamped together. Over time parts get loose and you start losing segments in the LED display and random error messages. The cases crack, the keyboards develop bad keys and and the On/Off switch becomes flakey. I am constantly having to open mine to replace parts pirated from other non-working Spices, so they are definitely high maintenance.

The Spices were a failed attempt by HP to match pricing of competitors such as TI, by making them cheaply, and it almost destroyed their reputation for producing premium quality calculators. They returned to their senses with the Voyagers, which are the highest quality and most durable calculators HP ever made.

I see, thanks for the explanation. As attractive as the 33/34/38 look in terms of features, I wouldn't want a high-maintenance unit that needs frequent repairs. Trying to clean the key contacts in my 41CV without damaging it further was plenty nerve-wracking enough.

The Voyagers certainly are the most durable HP - and possibly most durable calculators - ever made. Perhaps I ought to just get an 11C to go with my pair of 12Cs, 15C LE, and DM16L.
11-09-2019, 03:10 PM
Post: #13
 Trond Member Posts: 99 Joined: Sep 2017
RE: If I were to buy an LED model...
Interesting that you mention it. I have also had a HP 41CV for a while (haven't used as much as I thought because some keys are bugging me), and I recently bought a HP 34C in good condition(see the other thread on that).

The HP 34c is very good, and I'm frankly loving it. Unlike most LED calculators it has continuous memory, and root finder. I also really like the robust feel of the keys on this one. I really like the display too.

BUT many people have complained that the first batch of 34C was fragile, and often breaks down, while later batches were more robust (mine must be one of the latter). Also, before buying, take a good look at the battery lid and compartment, as this area can also often have problems.

HP 67 is said to be the most robust LED calc with one major exception : the wheel for the card reader which nearly always needs to be replaced. I was considering finding a 67 with a repaired wheel, but they are horrendously expensive.
11-09-2019, 03:49 PM
Post: #14
 mfleming Senior Member Posts: 448 Joined: Jul 2015
RE: If I were to buy an LED model...
(11-09-2019 02:30 PM)Dave Britten Wrote:  Wasn't quite sure what your comment meant, but after seeing the going rates for this low-end financial model, I think that narrows it down further to the 45 or 80.

I'd go for one of the Classics (nice solid handfeel) plus the HP Classic emulator board featuring the teenix multicalculator software. Dynamically switch between Classic, Woodstock, and Sting/Spice models. Programmable models can access a catalog of 50 or so programs and access them like mag cards. Load & save programs from the PC via USB or single-step through your program to find that last bug . You'll never grow tired of the models to play with, and panamatic's (sp?) keyboard overlays can be made to fit.

You can start with some of the HP25 and HP67 app pac programs, ready to transfer to the calc!
~Mark

Who decides?
11-09-2019, 04:00 PM
Post: #15
 Dave Britten Senior Member Posts: 1,179 Joined: Dec 2013
RE: If I were to buy an LED model...
(11-09-2019 03:10 PM)Trond Wrote:  Interesting that you mention it. I have also had a HP 41CV for a while (haven't used as much as I thought because some keys are bugging me), and I recently bought a HP 34C in good condition(see the other thread on that).

If some of the keys take a bit more force to register, then this is fairly easy to fix with a little Deoxit (red): use the precision tip to deposit a tiny amount of the fluid through the back of the PCB via the hole located under the keys in question. But the tricky part of it all is being very careful not to crack the screw posts, while also keeping the various pressure-fit connectors tight and clean enough. It probably took me at least 6 disassembly/reassembly cycles to get mine running reliably again after fixing a couple of the keys.

(11-09-2019 03:10 PM)Trond Wrote:  The HP 34c is very good, and I'm frankly loving it. Unlike most LED calculators it has continuous memory, and root finder. I also really like the robust feel of the keys on this one. I really like the display too.

BUT many people have complained that the first batch of 34C was fragile, and often breaks down, while later batches were more robust (mine must be one of the latter). Also, before buying, take a good look at the battery lid and compartment, as this area can also often have problems.

Perhaps all the marginal ones already broke down and were discarded before 1990, and all we're left with now are the more reliable specimens.

(11-09-2019 03:10 PM)Trond Wrote:  HP 67 is said to be the most robust LED calc with one major exception : the wheel for the card reader which nearly always needs to be replaced. I was considering finding a 67 with a repaired wheel, but they are horrendously expensive.

Yeah, that's kind of the "Achilles' wheel" of the 67, and just about any model with a card reader. Doesn't the repair just involve cleaning old gunk off the roller with an appropriate solvent, and popping on some new O-rings? Or is there more to it?

Honestly though, as heretical as it may sound, I'd probably opt for a TI-59 if I were buying a card-reader LED model. It's cheaper, more readily available, has more memory and more functions, has both a card reader and software ROM modules that can complement one another, plus it works with that great big printer dock. But if a 67 (or 97) fell into my lap, I certainly wouldn't say no!
11-09-2019, 05:37 PM (This post was last modified: 11-09-2019 05:38 PM by Trond.)
Post: #16
 Trond Member Posts: 99 Joined: Sep 2017
RE: If I were to buy an LED model...
(11-09-2019 04:00 PM)Dave Britten Wrote:  If some of the keys take a bit more force to register, then this is fairly easy to fix with a little Deoxit (red).....

Thanks. Not sure about it, but I think part of the calc might be slightly misaligned or bent out of shape. All the keys except one row (x, 1, 2, 3) register and feel perfect. But that row doesn't really "click" and I need to press harder. Otherwise this unit is near mint, so I am also cautious about opening it up (which is something I have never done to any HP calculator).
11-09-2019, 05:56 PM
Post: #17
 Maximilian Hohmann Senior Member Posts: 614 Joined: Dec 2013
RE: If I were to buy an LED model...
Hello!

(11-09-2019 04:00 PM)Dave Britten Wrote:  Honestly though, as heretical as it may sound, I'd probably opt for a TI-59 if I were buying a card-reader LED model. It's cheaper, more readily available, has more memory and more functions, has both a card reader and software ROM modules that can complement one another, plus it works with that great big printer dock. But if a 67 (or 97) fell into my lap, I certainly wouldn't say no!

So we are already two heretics here :-) After 40 years of owning my Ti59 I still like it very much an I would probably give away all my HP calculators (I have all LED models with the exception of an HP-35 "red dot") before parting with it.

There is absolutely nothing wrong about a Ti59. Some have bouncy keys (but this usually goes away with usage) and card reader problems just like their counterparts form HP. Occasionally I can't resist to buy one on eBay and now have two or three which cost me less than 10 Euros each. One even came with this monstrosity of a printer (it is really, really big for the little it does) that I never bothered to buy for my own calculator. What on earth am I supposed to do with these cash-register thermal paper printouts that fade within a couple of months?

One alternative not yet mentioned would be an HP-35. They can be found cheaply, with exception of the "red dot" variant, and most of them are working. At least you would then own the first scientific pocket calculator. That alone will impress your friends and familiy more than most that could be said about the other LED models. Apart maybe from the already mentioned HP-80 if you are into financial stuff. And if you happen to find a working HP-70 in good condition for less than 500$buy it! The calculator itself will calculate for you what a good investment you just made :-) Regards Max 11-10-2019, 10:49 PM Post: #18  Dave Britten Senior Member Posts: 1,179 Joined: Dec 2013 RE: If I were to buy an LED model... Thanks for all the input, everyone. I'm going to keep an eye out for a 45 and/or 80, and also try to get a 33C/E, 34C, and/or 38C/E if a good value turns up. And if the opportunity to snag a cheap (relatively speaking) 25 or 55 presents itself, I'll take it. 11-12-2019, 04:15 PM Post: #19  burkhard Senior Member Posts: 339 Joined: Nov 2017 RE: If I were to buy an LED model... (11-10-2019 10:49 PM)Dave Britten Wrote: Thanks for all the input, everyone. I'm going to keep an eye out for a 45 and/or 80, and also try to get a 33C/E, 34C, and/or 38C/E if a good value turns up. And if the opportunity to snag a cheap (relatively speaking) 25 or 55 presents itself, I'll take it. I'll second the 45. It's got a pile of improvements on the 35 (especially y^x instead of x^y) and a bunch of added functions via the shift key, but they are for sale cheap quite frequently. In the last couple of years, I've twice gotten ones from the auction site that were virtually perfect... no corrosion, no initials carved in, no used-up keys... both really good machines. One cost me$50 with shipping and the other $30 with shipping. The$30 one was exceptionally cheap, but I've seen others not too infrequently around $50. They are a great value and only cheaper than the 35 because they came second. True, it's not programmable, but as an ad hoc number cruncher, it's exceptional and SOLID. 11-12-2019, 06:37 PM Post: #20  teenix Senior Member Posts: 649 Joined: May 2016 RE: If I were to buy an LED model... (11-12-2019 04:15 PM)burkhard Wrote: I'll second the 45. I just got a HP45 for$Aus45.00. It's not supposed to work and I haven't fiddled with it yet, but I'm sure I can fix. The back label looks pristine and the battery contacts are clean, so it might just be a bit of corrosion inside. I'll try the blow dryer approach to raising the label to get inside. If the CPU board is cactus, I'll try one of Harald's replacement boards. It's missing a latch on the battery cover but I think there are 3d printed versions around.

cheers

Tony
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