I like to know why such an insane design. Seems like they put more effort on the power pack then the calculator. I'm sure Steve Wozniak had nothing to do with it.
You can make a removable battery holder with a 3 x AAA battery holder, and some foam as a spacer for the HP-35. AAA NiMH provides a longer run time than the original AA NiCad cells. The advantage being that if crafted in the right way and making contact pads on the bottom, you do not have to modify the actual calculator.
Are those magic batteries with no leaks after 52 years! Unlike HP today it was a high quality company then. I did hard wired the batteries on my HP-35.
I would start my squirting in some electronic contact Cleaner. Just sports them in and move the switch back-and-forth and commonly that helps. If that doesn’t get working, you will likely have to open it up and see if there’s a soldering issue in the switch. The wire to the switch might be loose.
The switch is essentially a couple of contacts on the PCB with a bent piece of copper that slides to make contact. The switch lubricant picks up crud over time and makes contact flaky. Best to disassemble the calculator, clean, and refresh the switch lubricant for reliable long time use. You can find instructions on the internet for disassembly. It’s tricky to remove the screws under the label without damage, but is possible.
That’s quite the complex battery cover design the HP engineers developed! Thanks for posting.
I like to know why such an insane design. Seems like they put more effort on the power pack then the calculator. I'm sure Steve Wozniak had nothing to do with it.
You can make a removable battery holder with a 3 x AAA battery holder, and some foam as a spacer for the HP-35. AAA NiMH provides a longer run time than the original AA NiCad cells. The advantage being that if crafted in the right way and making contact pads on the bottom, you do not have to modify the actual calculator.
HP35 was thee first pocket scientific calculator. Printing off the buttons was cost reduction from companies like TI. Gotta know what you’ve got.
Geo, would it be possible to 3D print a modified version of the original battery case, I.e., one that opens?
Are those magic batteries with no leaks after 52 years! Unlike HP today it was a high quality company then. I did hard wired the batteries on my HP-35.
It looks like that HP35 units has never been used. There’s no wear on the front after 52 years. There’s zero percent chance he just found them cheap.
Thanks for posting.
Geo, I have an HP55 that has a flaky power switch. Any ideas on how to proceed with a remedy?
I would start my squirting in some electronic contact Cleaner. Just sports them in and move the switch back-and-forth and commonly that helps. If that doesn’t get working, you will likely have to open it up and see if there’s a soldering issue in the switch. The wire to the switch might be loose.
@@Tatooinesky
Good suggestions. HP-35 has the same type of sliding power switch, its also flaky.
The switch is essentially a couple of contacts on the PCB with a bent piece of copper that slides to make contact. The switch lubricant picks up crud over time and makes contact flaky. Best to disassemble the calculator, clean, and refresh the switch lubricant for reliable long time use. You can find instructions on the internet for disassembly. It’s tricky to remove the screws under the label without damage, but is possible.