Topic: HP 25 charger question
I'm new to this forum and this is my first posting. Thanks to Jacques for adding me!
I have a little HP calcs collection and among them is my only Woodstock series calc, a HP 25 (unfortunately, not a 25C).
Quite normal, I'm having problems with the power supply. I do have the 82024A charger (it's the version with an applied sticker, so apparently a Classic series charger) and it does output the ~10V AC.
The calculator itself works fine (all keys, all digits) when I connect power from my lab power supply (2.8V DC) directly at the battery connectors. I did have heavy corrosion, though, (leaked very old rechargeable batteries from the person who sold it) but was able to remove it with a little bit of vinegar. Here's a photo:
I do have a battery pack "shell" and put two sully charged NiMH 1.2V rechargeable batteries in. Looks like this:
But the 25 won't turn on with this battery pack installed. I suspect there's a simple contact problem. My DMM says the voltage from the accu pack is 2.79V.
Do you guys have any hints for me what I can try/do to make my 25 work again on batteries?
Plus: when I plug the charger into the 25 (with the battery pack not installed) I just get weird blinking digits in the display. What does that mean? Can't the 25 be used with the AC adapter only? Is it a must to have a rechargeable battery pack installed when using the AC adapter?
Hint: I' very interested in electronics -- but haven't studied it and am just learning. I do have an oscilloscope and stuff but am still in the beginnings of understanding circuits ... ;-)