Repairing vintage calculators
Posted: Sat Jul 15, 2017 9:48 pm
I'm a total beginner in Electronics and Electrical Engineering. I'm a 68 year old retired IT Manager and for some years I've collected mainly HP and TI vintage calculators which I also program.
My current project is very personal to me; it's an HP-97 calculator\computer which appears to be dead to the world. It takes a 6v AC input from an HP adaptor (which I've tested and is supplying current) which also recharges a built in 4.5v DC battery pack. I've tested both battery packs I have and neither are holding any charge. I'm led to believe this calculator will only work with the power adaptor IF a working battery pack is in place and will run just on a charged battery pack. I've ordered a new battery pack which should be here in 2 weeks time. I've decided to take an online course in Electronics in the hope I may be able to fault find these problems myself.
Are there any members living in Sheffield, UK please who might be able to help me troubleshoot this HP-97, I do have a PDF of the Service Manual which shows all the circuitry.
Thanks
Dennis Tuckerman
My current project is very personal to me; it's an HP-97 calculator\computer which appears to be dead to the world. It takes a 6v AC input from an HP adaptor (which I've tested and is supplying current) which also recharges a built in 4.5v DC battery pack. I've tested both battery packs I have and neither are holding any charge. I'm led to believe this calculator will only work with the power adaptor IF a working battery pack is in place and will run just on a charged battery pack. I've ordered a new battery pack which should be here in 2 weeks time. I've decided to take an online course in Electronics in the hope I may be able to fault find these problems myself.
Are there any members living in Sheffield, UK please who might be able to help me troubleshoot this HP-97, I do have a PDF of the Service Manual which shows all the circuitry.
Thanks
Dennis Tuckerman