Happy Birthday to Me ...

[cjmcc]

I bought my first HP calculator back in high school. That HP29C saw me through the start of my engineering undergrad before it was displaced by the HP15C I still use. My younger sister used the HP29C, but somewhere along the line it disappeared.
While running GO25C as my smart phone calculator (thank you Olivier De Smet!) makes me smile, I missed my HP29C. Haptic feedback on a phone doesn't compare to the feel of a real calculator.
Prowling auction sites, I finally chased an auction for a working HP29C my wife will give me for my birthday in a few weeks. When I consider the $125 or so I spent in the late 70's is worth over $500 today, I feel better about the auction price.
So, while I won't consider myself a collector, my personal stash has working HP15C, HP35S, HP33S HP49G+ and HP50G, and a few malfunctioning HP48 units I want to try and repair some day.
   

[Bill Duncan]

I still have my original 29C.. While there are certainly more capable systems now and the HP-15C is a great shirt pocket calculator, it holds a lot of nostalgia for me as well. Olivier De Smet also has an HP-29C emulator which is very good btw.. I also have his go41cx and go48gx apps. Excellent.

While I have about 3 battery packs for the HP-29C which aren't working at the moment and need some repair, I have a friend that is going to 3d print me a battery pack.

Keep in mind that you don't want to use the charger directly on the HP-29C without a good battery pack or it'll smoke it! In my youth, I had the foresight to buy an external charging unit for the battery packs..

..and happy Birthday btw!
Cheers.

[Sylvain Cote]

(12-31-2017 07:52 PM)Bill Duncan Wrote:  While I have about 3 battery packs for the HP-29C which aren't working at the moment and need some repair, I have a friend that is going to 3d print me a battery pack.

FYI
Several designers (Nate Martin, Hans Brueggemann, Sven Gugelmann, Dave Frederickson, etc) have created several replacement parts for HP handheld.
For example: Woodstock Battery Top Part & Woodstock Battery Bottom Part
You can order a 3D print copy, from these Shapeways sellers: Nate Martin & Dave Frederickson
Sylvain
Edit: added designer names

[Bill Duncan]

Thank you Sylvain! Excellent! I've put a set on order..

[cjmcc]

Birthday came, so I was allowed to open the EBay package!
Calculator, case, and reference card all looking good. Battery pack is intact, but I have no idea of the condition of the NICADS or any way to charge them.

(12-31-2017 08:09 PM)Sylvain Cote Wrote:  FYI
Several designers (Nate Martin, Hans Brueggemann, Sven Gugelmann, Dave Frederickson, etc) have created several replacement parts for HP handheld.
For example: Woodstock Battery Top Part & Woodstock Battery Bottom Part
You can order a 3D print copy, from these Shapeways sellers: Nate Martin & Dave Frederickson
Sylvain
Edit: added designer names

I went the single piece approach using Chris Osborne's design, also available on Shapeways from MafWorld . Since the design files were available, I was able to 3-d print the holder, now I just need to figure out a decent spring arrangement to connect the cells and hold them in place. Then I'll add a pair of Eneloops, and hopefully I'm off to the races.

[Bill Duncan]

(01-23-2018 08:04 PM)cjmcc Wrote:  Birthday came, so I was allowed to open the EBay package!
Calculator, case, and reference card all looking good. Battery pack is intact, but I have no idea of the condition of the NICADS or any way to charge them.

(12-31-2017 08:09 PM)Sylvain Cote Wrote:  FYI
Several designers (Nate Martin, Hans Brueggemann, Sven Gugelmann, Dave Frederickson, etc) have created several replacement parts for HP handheld.
For example: Woodstock Battery Top Part & Woodstock Battery Bottom Part
You can order a 3D print copy, from these Shapeways sellers: Nate Martin & Dave Frederickson
Sylvain
Edit: added designer names

I went the single piece approach using Chris Osborne's design, also available on Shapeways from MafWorld . Since the design files were available, I was able to 3-d print the holder, now I just need to figure out a decent spring arrangement to connect the cells and hold them in place. Then I'll add a pair of Eneloops, and hopefully I'm off to the races.

There are a couple of recent threads here on woodstock batteries. One of the threads has a source to springs. The other option mentioned in the threads are doing surgery on the battery pack and replacing the cells. This works for me and has the advantage of coming with a spring already..

Two basic approaches;
- the one I used was to cut one end (the one with the terminals) of the crosspiece out. You can then spread the sides slightly to pull the cells out one-by-one.
- the other approach is to notice how HP did it themselves. Slice the bottom off with an exacto knife.