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Maximilian Hohmann · 02-22-2024, 09:58 PM

Hello,

in case someone wants to buy an HP 20b, maybe with the intention to convert it to a WP-34s or WP-31s, might find the ongoing sale of german calculator store "Dynatech" interesting: In their eBay shop (named dynatech2005) they currently sell these calculators new for 12,49 Euro, even cheaper if you buy more than 4. Free shipping within Germany included.

I already have a couple, but at that price I couldn't resist, since I still have a set of keyboard stickers and a programming cable somewhere. And even if I can't find this stuff, the HP 20b is one of the prettiest calculators ever made. In my view.

Regards
Max

ht003 · 02-23-2024, 07:59 AM

Thank you for the hint. I just bought it for 12.49 Euros! :-)

Pierre · 02-23-2024, 12:05 PM

(02-22-2024 09:58 PM)Maximilian Hohmann Wrote: ... but at that price I couldn't resist...

Thanks for the information.
But be careful : Don't take the wrong calculator at Dynatech2005: they sell a TI-83 Plus for over €1400 !!!

LarsF · 02-24-2024, 10:07 AM

It was a very good price but they would not sell to Sweden Sad

ht003 · 02-26-2024, 06:26 PM

Hi,
I just received the HP20B from dynatech. It came in perfect condition (factory sealed) with two new batteries. The old ones were dead.

I could not resist to order a second one (only god knows why).

Cheers

Maximilian Hohmann · (This post was last modified: 02-26-2024 07:27 PM by Maximilian Hohmann.)

Hello!

(02-26-2024 06:26 PM)ht003 Wrote: I just received the HP20B from dynatech. It came in perfect condition (factory sealed) with two new batteries. The old ones were dead.

The same with mine, but they still have 2.9V each. This should be good enough to power less demanding devices. Interestingly these calculators were intended for the Asia/Pacific region, which among other things can be seen from the second manual that is included with the english one. I wonder how a box of these surfaced 15 years later in Germany...

(02-26-2024 06:26 PM)ht003 Wrote: I could not resist to order a second one (only god knows why).

I ordered two right away :-) Now all I have to find is the programming cable.

Regards
Max

SammysHP · 02-26-2024, 07:59 PM

(02-26-2024 07:27 PM)Maximilian Hohmann Wrote: I ordered two right away :-) Now all I have to find is the programming cable.

I'd be more interested in some overlays. That's what stops me from buying a few right now. Smile

Maximilian Hohmann · 02-26-2024, 08:42 PM

Hello!

(02-26-2024 07:59 PM)SammysHP Wrote: I'd be more interested in some overlays. That's what stops me from buying a few right now.

I got two sets from Jaco Mostert (a member of this forum) last year, but I don't know if he has any left.

Regards
Max

Didier Lachieze · 02-26-2024, 09:41 PM

I would suggest to contact spiff72 for WP34S overlays, see here for more details.

johnb · 02-26-2024, 09:56 PM

(02-22-2024 09:58 PM)Maximilian Hohmann Wrote: ...the HP 20b is one of the prettiest calculators ever made...

It's a shame that they made the 20b the nicer-looking of the two!

I really like the keys of the 30b, but you're right, the 20b is pretty.

[Mumble mumble think think... wondering whether I could transplant a 30b into a 20b case without wrecking it, then flash it into a WP-31/34...]

ht003 · 03-05-2024, 07:25 PM

The seller dropped the price for the HP 20B: It is now 8.42€. He also offers a HP 39gs for 11.49€ including shipping. Now it’s the right time to buy and buy …. ;-)

floppy · 03-05-2024, 09:07 PM

(02-24-2024 10:07 AM)LarsF Wrote: It was a very good price but they would not sell to Sweden

You need one?
DM me.

Raymond Del Tondo · 03-06-2024, 01:01 AM

(02-26-2024 07:59 PM)SammysHP Wrote: I ordered two right away :-)

Altough I don't really need one of these, I just bought one, too.
For 8,49 Euro as new it's the cheapest HP RPN capable calc currently available.
Since my only use for this unit is as a four-banger,
I would not need any key legend overlays,
but a full size anti-glare overlay for the area between the keys;-)

SammysHP · 03-07-2024, 08:50 PM

Awesome, immediately ordered a few! Now let's see if I have all parts to build a programming cable (is there a 3D model to print a matching connector? I have a programmer and bags of pogo pins etc. available, just need something to hold them in place).

SammysHP · (This post was last modified: 03-11-2024 09:39 AM by SammysHP.)

Today they arrived, together with a pack of fresh CR2032! Nice!

Unfortunately my attempts at flashing the firmware were not successful so far. I made a connector with pogo pins and a little PCB for the reset and erase buttons.

[image]

Erase worked fine. The serial connection not so much. I only found a CH340 and a PL2303 USB-TTL adapter in my box, neither of them worked. Tried it under Linux (wp34sflashcmd) and Windows (MySamBa).

While I would like to fix my setup, I'd also be happy if someone could flash them for me. Anyone with the proper hard- and software in the area of Hanover, Germany?

Update: Found an FTDI adapter and it worked smoothly under Linux with wp34sflashcmd!

sunpazed · 03-09-2024, 11:30 PM

I was looking to order one of these, however they only ship within the EU. Won’t deliver to Australia. I could use a drop-shipping service, but then I’d be paying way more for the shipping than the calculator!

Erhan · 03-11-2024, 07:36 AM

Hello to all members,

thank you for the hint about the sale in germany. I have also picked up two 20b models which are arrived on saturday for me.

(03-09-2024 06:28 PM)SammysHP Wrote: Unfortunately my attempts at flashing the firmware were not successful so far. I made a connector with pogo pins and a little PCB for the reset and erase buttons.

I have used a usb ttl adapter with a silicon labs chip in it, at least the drivers are from the website. I have followed the instructions "Flashing a WP34s using Arduino Nano.pdf" which is available on the source forge site. I have tried it with the figure one schematic but it didn't work at first. On the usb to ttl adapter the tx and rx lines are written on the silkscreen. After I switched the rx and tx line to the calculator pins I was able to flash the wp34s full bin software with the samba.exe application. It took about 17 seconds. Maybe you can try this as well.

dg1969 · 03-11-2024, 05:09 PM

No delivery to France either obviously…

floppy · 03-12-2024, 05:03 PM

If anybody will go in october to allschwill, let the parts being delivered there or to a person who will go there. then you can get your part there.

SammysHP · (This post was last modified: 03-25-2024 09:30 PM by SammysHP.)

(03-11-2024 07:36 AM)Erhan Wrote: On the usb to ttl adapter the tx and rx lines are written on the silkscreen. After I switched the rx and tx line to the calculator pins I was able to flash the wp34s full bin software with the samba.exe application.

Usually RX goes to TX and vice versa. It's always from their respective point of view.

As mentioned in my update, it worked with an FTDI adapter. Seems to be very finicky with the timing and the PL2303 and CH340 might be slightly different.

I know, I'm late to the party, but let me tell you my first impressions of the WP firmware: For the WP 34s you really need an overlay. Too many functions on each button with three shift keys.
The WP 31s on the other hand can be used with a few minutes of memorizing the important buttons. As a reference I printed the layout on a small piece of paper and glued it to the backside of the calculator. Using it as a four-banger for quick number crunching that's sufficient. Only functions I miss so far is the integer mode with base conversion!

edit: Just noticed that my serial numbers are pretty close, within 10. So they appear to be still in their original box and taken out top down! Wonder where they found that pallet.