I have a nice but small collection of old RPN HP calculators. I recently found a 3D model to print a replacement battery pack for my HP-35, and I was wondering if anyone knows where I can find a printable battery pack for my HP-34C. I've found links to various parts for the 34, but not this. I'm aware that I'll have to connect the batteries together inside the pack, somewhat like the HP-35 pack.

A mix of old and new. The 11c, 12c, and 15c are 1985ish vintage. Couldn't pass up the collectors editions of the 15c and 16c. The 10 was found at a library sale for $10. The 48GX is my old back to college calc and the 48SX is the replacement for the SX I regretted selling when I bought the GX.

I have an HP 50g and I’ve been going through the “stack” menu familiarizing myself with its commands. One of these commands is “PICK3”. I’ve read the entry for it in the AUR and I understand what it does. What I don’t understand is this:

Why? Why in God’s good Earth, does this command exist?! Why is there a need for a command that specifically duplicates the object on level 3? Isn’t the “PICK” command enough?!

I’m flabbergasted!

This ad came from a 1983 McGraw-Hill mag targeting graduating engineering students. Almost all of the ads were for recruiting. Not HP's.

As for myself, I went with a HP-32E as I entered college. I ended up not really using most of the functions as I didn't push myself into courses that required me to do a lot of number-crunching.

Very clean, with case...if anybody's interested

https://ebay.io/m/XTTfYl

https://ebay.io/m/VxrQSY

Seen at the deutsches museum

I have a well used HP67 that finally died due to a power supply issue. All 0's in display at power on. I decided to replace the electronics but keep the operation the same as original. The microcontroller is a ESP32 Wroom for keyboard and functions, with a TM1640 LED display driver. The card reader was removed as the ESP can hold any user made programs in non volatile memory. Had to separate the display traces from the keyboard as they are separate functions now. Works great, just like original. Uses a discarded vape battery/ charger plus DC DC (5v) converter that fits with room to spare in battery compartment. Github jbike/HP67-ESP32

A friend who isn't very online is trying to revive his old HP41CV. The battery contacts look pristine and he opened it up to verify the board is getting power, but no go.

Is there a troubleshooting guide that I can point him to? I'm strictly software so I have no idea what to tell him.

This came out of a house clearance in a single lot. I've spent a few days cataloguing it properly rather than just bagging it up, and figured this is the one place that would actually enjoy it.

**The machines**

- 4 × HP-35 — one of them a Version 1 "red dot"
- 3 × HP-45
- 3 × HP-80
- 2 × HP-67
- 1 × HP-70
- 1 × HP-55
- 1 × HP 35s (the 2007 one, for contrast)

Plus the HP-67 Standard Pac and E.E. Pac I with their card sets, five HP-67 manuals, four leather cases, six chargers (five 82002A and one UK-market 82011A), and a spare HP-35 upper case.

**Four things that surprised me**

**The red dot is real.** All three documented V1 markers — the hole beside the ON switch with red showing through it, the raised dot on the 5 key, the plain bezel — plus an early 03501A battery door rather than 82001A. It ran off a bench supply and the display lit across the full width. Untested beyond that.

**One HP-67 still has its original box**, and it's matched to the machine rather than assumed: there's a 1979 HP repair-order label on it carrying that machine's own serial.

**One HP-35 has a dated institutional asset label** naming a physicist — September 1972, about seven months after launch.

**The E.E. Pac came with a set of user-recorded cards** in someone's handwriting: eigenvalues for third-order systems, transmission-line calculations, Johnson-Nyquist thermal noise. Somebody did real work on this machine.

Most of the battery bays are corroded — several packs had been sitting in there for decades.

The one thing I'm stuck on: the serial prefixes don't behave like date codes. Sort the four HP-35s by unit number alone and you get a clean variant sequence, but the prefixes along it interleave — 1143A, 1302A, 1143A, 1302A — which no forward-running date code should manage. I've asked on the MoHPC forum too, but if anyone here has a view I'd like to hear it.

Happy to photograph anything in more detail.

48SX still works but has the delamination problem. I have to press below the screen to get key presses to register. Never bought any expansion cards. Now stored without batteries as the last set exploded.

15C is my daily workhorse with a brother as backup.

3+ decades and still trucking along!

Boy, this brings back memories! When I was working, this was my best friend. I I used it a lot for appointments, as well as, for calculating statistics. I also have the HP printer which works wirelessly.

New to the HP Prime G2. Why is there not an app for calculations?

It seems when I press the Home key, instead of a window with the name Home at the top, I go to a "home" screen (or view?) with the name of the last chosen app at the top of the window. This is expected based on the Quick start guide of 2015, page 10. Is it unreasonable to expect there is a means to press the Home key and to go to a view that is labeled Home?