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Advice on Purchasing an HP
09-20-2018, 07:22 PM
Post: #1
Advice on Purchasing an HP
Hi all, just stumbled onto this site looking for some info on the amazing HP calculators.

Recently had a sour eBay experience buying a 28S, was sold as working but one of the rows was completely dead. Did get a full refund but I'm a bit disappointed with the lack of access to the internals of the calculator.

I'd really like to have one, but I worry that in the long run it will suffer the same fate and become more of a display item than the working piece of history I'd prefer it to be.

So I'm just curious if any of the other models are a bit easier to maintain? I have no issue spending the money on a nice one but I'm concerned of its longevity.
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09-20-2018, 09:36 PM
Post: #2
RE: Advice on Purchasing an HP
I think your experience on the 28S was somewhat unusual, although keep in mind it 30 years old or close to it, so anything is possible. More likely those 28C/S (like all the clamshells excepting a late production 19BII) might have broken / cracked battery door issues. Many of those sold on eBay already have that problem and even if you get a good one, you need to be careful with that, as it is a fragile point on that calculator. Still the 28S is a nice machine and not super crazy expensive. I have a nearly perfect one which is a joy to use.

Almost every series has *some* weak point, but treated reasonably well, you can buy one that has lasted for decades and will keep doing so. Some of the problems can be repaired easily, some less so.

Still, I'd
1) Figure out what model does what you want and then
2) Learn its weak points (ask here) and things to look for buying one used.

Was the 28S otherwise your "dream machine"? If so, I'd get another (ask for pictures of the battery door and surrounding area on the calculator itself).
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09-20-2018, 10:01 PM
Post: #3
RE: Advice on Purchasing an HP
Depending on how much you are willing to spend, this may be of interest:

https://www.ebay.com/itm/Vintage-HP-28S-...SwW55bb6Hs

Good looking calculator with manuals.

Good luck!

smp
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09-20-2018, 10:43 PM
Post: #4
RE: Advice on Purchasing an HP
(09-20-2018 10:01 PM)smp Wrote:  Depending on how much you are willing to spend, this may be of interest:

https://www.ebay.com/itm/Vintage-HP-28S-...SwW55bb6Hs

Good looking calculator with manuals.

Good luck!

smp

As another option you might consider posting your "want" on the "Classifieds" forum here on the Museum. The Auction Site (TAS - that's what we call ebay here) is always a bit of a gamble. Primarily I think because many (if not most)of the sellers on TAS are not especially knowledgeable about calculators.

Pretty much everyone on this forum knows calculators, especially HP, and if they have one to sell they will tell you accurately about its condition.

John
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09-21-2018, 12:00 AM
Post: #5
RE: Advice on Purchasing an HP
(09-20-2018 07:22 PM)burgarwulf Wrote:  Hi all, just stumbled onto this site looking for some info on the amazing HP calculators.

Recently had a sour eBay experience buying a 28S, was sold as working but one of the rows was completely dead. Did get a full refund but I'm a bit disappointed with the lack of access to the internals of the calculator.

I'd really like to have one, but I worry that in the long run it will suffer the same fate and become more of a display item than the working piece of history I'd prefer it to be.

So I'm just curious if any of the other models are a bit easier to maintain? I have no issue spending the money on a nice one but I'm concerned of its longevity.

IMO your best bet is the DM-42S, not exactly HP from the golden era, but with the exception of the keyboard, everything else is excellent and far superior to HP's.
All good HP calcs are nowdays old enough and not being "serviceable" isn't make them good buy.
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09-21-2018, 12:23 AM
Post: #6
RE: Advice on Purchasing an HP
Though it is a different form factor, you may want to consider an HP48GX. They are not too expensive and much more capable than the 28S, especially since the 48 has 2-way serial communication which the 28 lacks.

There are literally thousands of programs available for the 48 series from hpcalc.org and other sites.
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09-21-2018, 02:42 AM
Post: #7
RE: Advice on Purchasing an HP
The HP-35S can be currently purchased new, online (albeit not from hp.com - out of stock) for ~~$50.

Check out NQ41!
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09-21-2018, 03:01 AM
Post: #8
RE: Advice on Purchasing an HP
I'd echo the suggestion of an HP48 if you can get one. I have both a 28 and a 48. The hinge on the 28 is an amazing bit of engineering, but is also another failure point. My 48 has worked flawlessly since I picked it up halfway through my university days.

And yeah, if you want new- and RPN, the Swiss Micros DM42 can't be beat. The DM41 is a lot of fun, too, and slightly smaller (also RPN). One nice thing about the various Swiss Micros machines is you can easily get stuff on and off of them via USB. If you get a '48, you have to mess with USB to serial and get a special cable if you want to copy anything on or off of it.

Regardless, have fun! Amazing machines.
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09-21-2018, 04:28 AM
Post: #9
RE: Advice on Purchasing an HP
(09-21-2018 12:00 AM)RMollov Wrote:  
(09-20-2018 07:22 PM)burgarwulf Wrote:  Hi all, just stumbled onto this site looking for some info on the amazing HP calculators.

Recently had a sour eBay experience buying a 28S, was sold as working but one of the rows was completely dead. Did get a full refund but I'm a bit disappointed with the lack of access to the internals of the calculator.

I'd really like to have one, but I worry that in the long run it will suffer the same fate and become more of a display item than the working piece of history I'd prefer it to be.

So I'm just curious if any of the other models are a bit easier to maintain? I have no issue spending the money on a nice one but I'm concerned of its longevity.

IMO your best bet is the DM-42S, not exactly HP from the golden era, but with the exception of the keyboard, everything else is excellent and far superior to HP's.
All good HP calcs are nowdays old enough and not being "serviceable" isn't make them good buy.

"IMO your best bet is the DM-42S, not exactly HP from the golden era, but with the exception of the keyboard....."
could you elaborate more on that; what is exactly the problem with the keyboard?
is it just stiffness issue? or a build-quality issue?
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09-21-2018, 06:23 AM
Post: #10
RE: Advice on Purchasing an HP
(09-20-2018 09:36 PM)burkhard Wrote:  I think your experience on the 28S was somewhat unusual, although keep in mind it 30 years old or close to it, so anything is possible. More likely those 28C/S (like all the clamshells excepting a late production 19BII) might have broken / cracked battery door issues. Many of those sold on eBay already have that problem and even if you get a good one, you need to be careful with that, as it is a fragile point on that calculator. Still the 28S is a nice machine and not super crazy expensive. I have a nearly perfect one which is a joy to use.

Almost every series has *some* weak point, but treated reasonably well, you can buy one that has lasted for decades and will keep doing so. Some of the problems can be repaired easily, some less so.

Still, I'd
1) Figure out what model does what you want and then
2) Learn its weak points (ask here) and things to look for buying one used.

Was the 28S otherwise your "dream machine"? If so, I'd get another (ask for pictures of the battery door and surrounding area on the calculator itself).

I wouldn't necessarily say dream machine, but I do find the dual keyboard appealing for whatever reason. I'm a big fan of HP test gear as well and I was wanting a real calculator (phones work...but it just has an unnatural feel to me, plus the screen cutting out) for general work purposes.

I'm glad to hear that was likely a more rare situation, I have been doing some repair work on other gear and so was hoping the 28S would be approachable. Think it was the first google result that killed that dream off.

It had already been partially opened so I finished the deed as it were as carefully as I could. She still works, but that row will not respond regardless of my attempts. I haven't had the time to get any further in to it than some simple tests of the key pad itself. I will say it has one of the nicer looking PCBs I've ever had the luck of seeing.

(09-20-2018 10:01 PM)smp Wrote:  Depending on how much you are willing to spend, this may be of interest:

https://www.ebay.com/itm/Vintage-HP-28S-...SwW55bb6Hs

Good looking calculator with manuals.

Good luck!

smp

Had actually been eyeing that one since I discovered the last one had been refunded.

(09-20-2018 10:43 PM)John Cadick Wrote:  As another option you might consider posting your "want" on the "Classifieds" forum here on the Museum. The Auction Site (TAS - that's what we call ebay here) is always a bit of a gamble. Primarily I think because many (if not most)of the sellers on TAS are not especially knowledgeable about calculators.

Pretty much everyone on this forum knows calculators, especially HP, and if they have one to sell they will tell you accurately about its condition.

John

I stumbled into that section after posting this, and I'll definitely have to keep that in mind.

(09-21-2018 12:00 AM)RMollov Wrote:  IMO your best bet is the DM-42S, not exactly HP from the golden era, but with the exception of the keyboard, everything else is excellent and far superior to HP's.
All good HP calcs are nowdays old enough and not being "serviceable" isn't make them good buy.

(09-21-2018 12:23 AM)John Keith Wrote:  Though it is a different form factor, you may want to consider an HP48GX. They are not too expensive and much more capable than the 28S, especially since the 48 has 2-way serial communication which the 28 lacks.

There are literally thousands of programs available for the 48 series from hpcalc.org and other sites.

(09-21-2018 02:42 AM)Craig Bladow Wrote:  The HP-35S can be currently purchased new, online (albeit not from hp.com - out of stock) for ~~$50.

(09-21-2018 03:01 AM)KF6GPE Wrote:  I'd echo the suggestion of an HP48 if you can get one. I have both a 28 and a 48. The hinge on the 28 is an amazing bit of engineering, but is also another failure point. My 48 has worked flawlessly since I picked it up halfway through my university days.

And yeah, if you want new- and RPN, the Swiss Micros DM42 can't be beat. The DM41 is a lot of fun, too, and slightly smaller (also RPN). One nice thing about the various Swiss Micros machines is you can easily get stuff on and off of them via USB. If you get a '48, you have to mess with USB to serial and get a special cable if you want to copy anything on or off of it.

Regardless, have fun! Amazing machines.

The 48 does look like a very nice version as well. Looks considerably more solid build wise.

I'm actually really surprised HP's website has that 35S listed, I didn't even bother looking there when I started my search.

I shouldn't have looked at those Swiss Micros though. Way too tempted by those even in addition. At first I had mistaken another retailer I'm familiar with, Micro Swiss, which didn't make much sense as they're a manufacturer of 3D printer parts!

Thank you for all the information, was a bit surprised by all the responses. Taken a lot into consideration and I will post after some more thought!
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09-21-2018, 08:02 AM (This post was last modified: 09-21-2018 08:10 AM by RMollov.)
Post: #11
RE: Advice on Purchasing an HP
(09-21-2018 04:28 AM)zx_spectrum Wrote:  is it just stiffness issue? or a build-quality issue?
It's a complex thing. Key size, key legends, key shape, key feel. Grab any 20+ years old HP like 41 or 42 or even 48. (IMO 41 is the best by far.) Hit a few buttons. Grab the DM42, do the same and you'll know what I mean immediately. After I performed the suggested fix, my DM42 is definitely useable, but still far away from those old beasts. Compare the force needed to register. In DM42's case ENTER vs any other key. It all works together and HP got it damn right back then.
More to the point, yes, the stiffness. Build-quality is fine, given the design. Let alone double-moulded keys... I realise today it is absurd to have such high class hardware for something in this area, so again - DM42 is by far the best bet.

I like RPL better then RPN and I wouldn't compare HP28 and HP48 to HP42, the latter loses in any case. But still, DM42 rules calculator world of today. IMO, of course Smile


Cheers,
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09-21-2018, 09:54 AM (This post was last modified: 09-21-2018 10:02 AM by brickviking.)
Post: #12
RE: Advice on Purchasing an HP
I've heard all the recommendations here, but nobody's spoken up for the 50G. The laugh is that I would happily recommend the 50G over anything else. Yes, the 48GX is more "classic" and yes it's true that there are literally thousands of programs for it. A lot of those same programs may work as-is on the 50G, or there are more modern replacements specifically for the 50G. Here's my list of pros and cons for the 50G:
Pros:
  • USB/serial/IR connectivity. (48GX only has serial and IR).
  • SD card up to 2GB unless you have newRPL (alpha software). 48GX only (officially) has cards up to 4MB and those are very hard to get.
  • Faster speed (on average, 7 - 10 times faster than the 48GX).
  • More recent firmware (2009), and libraries that used to be an add-on for the 48GX are now built-in.
  • Screen is clearer than most of the earlier 48GX family, though if you get a "proper" black screen on the 48GX, it comes closer.
  • Screen is larger in pixels (131x80 instead of 131x64). This can allow for displaying more stack levels in RPL.
  • Uses four AAA batteries and a CR2032, so a set of batteries lasts longer. In addition, if you plug in the USB cable, you can power the calculator off it, though it won't charge batteries.
  • Like the 28S and 48 family, it uses RPL with a stack only limited by available memory.

Cons:
  • Not sold by HP any more; though you can still buy them on sites like Amazon, prices aren't as cheap as they were. In comparison, the 48GX hasn't been sold by HP for decades and is really only available second-hand, and very few New-In-Box 48GX units exist through the major retailers.
  • Not all 48GX programs are compatible with the 50G, especially those using SysRPL.
  • IR is not quite compatible with the 48GX or the printer. Range is considerably reduced over the 48GX.
  • Paper manuals, when you can get them, are reportedly not of the same quality of writing as the 48GX.
  • Though you can still get 2GB SD cards, they're starting to get harder to get.
  • Some USB drivers can be dicky, especially considering the Windows 10 eco-system.
  • No memory expansion—either ROM or RAM—beyond that already on the device. This also means that cards for the 48GX won't work (as is) on the 50G, as there's simply no place to put them. They may work if rewritten as a library, and modified for the 50G environment.
  • The ENTER key isn't in the "canonical" place, as it is on the 48GX and some earlier calculators. There have been religious wars about this one key and its placement.
  • It's not as "classic" as the 28S/41C/42S, though it doesn't have the same weaknesses.
  • The UI is different from the 48GX, though it's debatable whether it's worse or the same.

I'll leave others to produce a set of pros and cons for the 48GX; I don't have one so I'm not qualified to comment on its strengths and weaknesses.

Both the 48GX and the 50G have emulation options available on the PC in the excellent EMU48 (or EMU48+) (Windows) and x49gp (Linux/OSX only). x48 also exists for Linux, but doesn't hold the same degree of support as EMU48. That way, you can evaluate the interface for both at your leisure before deciding to purchase either. Most other HP calculators also have PC emulators, though you may have to hunt a little for them.

(Post 286)

Regards, BrickViking
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09-21-2018, 10:02 AM
Post: #13
RE: Advice on Purchasing an HP
Examples of the HP-48G/S/X are not always easy to come across even if they would be an excellent replacement for the 28S. Back in the day I "graduated" from the 28S to the 48GX so I can confirm that the 48GX (or similar) is the closest to the 28S that you'll get nowadays without actually getting a 28S.

Another alternative you might wish to consider is the 50g. It's still an RPL machine in the lineage of the 28S and 48 gang but with more memory, more speed, bidirectional communication and an SD card slot. It still works with the HP-82240A/B printer just like the 28S and its successors.

The only real problem with the 50g that won't be fixed stems from the fact that it is actually an ARM CPU emulating the HP Saturn CPU and, because of the hardware differences, alarms don't switch the machine on if they become due when it's off.
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09-21-2018, 10:03 AM
Post: #14
RE: Advice on Purchasing an HP
(09-21-2018 09:54 AM)brickviking Wrote:  I've heard all the recommendations here, but nobody's spoken up for the 50G.

You just beat me to it Smile
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09-21-2018, 01:01 PM (This post was last modified: 09-21-2018 02:26 PM by burkhard.)
Post: #15
RE: Advice on Purchasing an HP
(09-21-2018 09:54 AM)brickviking Wrote:  Cons:

I've got a few HP50g as well. You left off one of my biggest cons with it--it's bloody ENORMOUS!
The HP48 (and I bought one new in the early 90s and still have it) is pretty big as well.
These are both desk calculators.

As some other folks alluded... figure out first if you like RPL or pure RPN. I've got a bunch of both and for my needs I really prefer straight RPN. My programs are fairly simple, especially these days, and I find tougher to remember RPL intricacies for occasional programming tasks. I find RPL a steep learning curve which gets complicated by symbolic math provisions (exact and approximate values) that most people don't need. If you want symbolic math, you need one of these RPL machines, though.

The RPL calculators do tend to be pretty big in general, so factor that in. Also, keep an eye on the displays. The early ones (HP28, HP48 blue-screen) tend to be rather low contrast.

If you like plain RPN and are not a collector, but a user, I would seriously consider the DM42 as well. It's based on the HP42S, a fantastic machine, but is much faster, has a far better display, and easy I/O with a PC. It's not cheap ($200), but is built stoutly, and has a devoted active cult following, and is in active production. A real HP42S tends to be about as pricey--they are highly sought after. Both are very pocketable. If you want a graphing calculator, they are not a good choice, though... very rudimentary in that respect.

I have a 35S as well. It's cheap, looks great, is compact, and RPN, but it's got some things I truly hate:
1. Display is weird / ugly proportions (subjective) / a step backward for a fairly modern calculator.
2. No rectangular ↔ polar functionality.
3. Complex number handling clumsy
4. Number base operations & integer arithmetic (binary, hex, &c.) clumsy.
5. Alpha capability / labeling limited.

I give the 35S to my kids to brainwash them into RPN. If they damage them, it's not the end of the world.
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09-21-2018, 10:34 PM
Post: #16
RE: Advice on Purchasing an HP
(09-21-2018 01:01 PM)burkhard Wrote:  
(09-21-2018 09:54 AM)brickviking Wrote:  Cons:

I've got a few HP50g as well. You left off one of my biggest cons with it--it's bloody ENORMOUS!
The HP48 (and I bought one new in the early 90s and still have it) is pretty big as well.
These are both desk calculators.

Yes, they're big, and certainly far bigger than the HP42S. I'd forgotten that, as I've got three calculators that size, and it seems to be an inevitable price for the larger display. I mean, who wouldn't want ten lines of stack instead of one? I'm just used to it, and besides which, the calculator still fits in my pocket, so I somewhat disagree that they're desktop calculators. When I use any of my "big" calculators, I don't typically use them on the desk, I mostly use them in my hand, and they're a comfortable fit in my size hand.

I'd have to agree with the point of RPL having a steep learning curve too, I'd forgotten to mention that earlier. I'm barely getting to grip with the basics, but it's still going to be my go-to platform for the programs I've made.

(Post 287)

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09-21-2018, 11:18 PM
Post: #17
RE: Advice on Purchasing an HP
(09-21-2018 09:54 AM)brickviking Wrote:  Both the 48GX and the 50G have emulation options available on the PC in the excellent EMU48 (or EMU48+) (Windows) and x49gp (Linux/OSX only). x48 also exists for Linux, but doesn't hold the same degree of support as EMU48. That way, you can evaluate the interface for both at your leisure before deciding to purchase either. Most other HP calculators also have PC emulators, though you may have to hunt a little for them.

I second the recommendation of trying emulators before you buy. Free42 is another excellent emulator, available for cell phones as well as PC's

If you have no HP calculator programming experience you would be well advised to try programming both RPN and RPL models to see which (if any!) you prefer.
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09-22-2018, 04:56 PM
Post: #18
RE: Advice on Purchasing an HP
I say look for a 48SX. They're built like tanks, in my experience, and quite a bit less expensive than the 48GX. You might be able to get a 48S even cheaper, but only go that route if you're 100% sure you don't need the card slots. (Even if you don't plan to buy a rather expensive RAM card, the Solve/Equation Library ROM card adds quite a bit of utility.)
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09-22-2018, 10:06 PM
Post: #19
RE: Advice on Purchasing an HP
Easy to maintain...

I would echo the recommendations for both the HP 48G and HP 50g series. Try to avoid the 49g+ if you can because the keyboards of the 49g+, especially the early production around 2003, has bad keyboards (speaking from owning two that a key broke off). The 48gII may be an option (try to go for the later production, since it would have 256K RAM, but no SD cards). My first picks would be the 48G, 48S, or 50g.

If you want something on the small, portable factor, I'm thinking either the 11C or 15C (they are both slow (unless you get the 15C Limited Edition) and more expensive).

If your budget is a bit larger, the 42S is always a favorite. The 41C is also solid (they will need N batteries).

Hope that helps.
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09-25-2018, 06:52 AM
Post: #20
RE: Advice on Purchasing an HP
If you don’t get a 50G now it might become difficult to afford in a few years. I have two (user and NIB spare) and the spare lives in my safety deposit box along with a bunch of programs and libraries on an SD card.

For day to day use I prefer the DM 42 or the WP-34s. The 28s is a fine machine but storage is a bit limited and it has no serial port. Get some emulators and go nuts. If you can program in BASIC the 71b might be more your speed but there are some old retired guys here who bid them up as far as you care to go because you need a user and NIB of every ROM revision if you’re a real collector Wink
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