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HP 45 display malfunction
02-25-2019, 11:00 PM
Post: #1
HP 45 display malfunction
HP 45 purchased 11/1/73 from Mich Tech Bookstore ~$400.
When powered on "all" display digits flash red 8's, decimal (currently at 2 digit accuracy) and
the "-" sign on the far left. I believe the display is fully functional (meaning no partial digits) as are all of the keys. After a period of time the display goes blank. If allowed to warm up the display goes blank more quickly. Otherwise this vintage calculator appears to be in "Very Good" condition. There is no corrosion in the battery compartment. All four rubber foot pads are in good shape as is the battery compartment cover. The original rechargeable battery was discarded years ago and I ran it directly on the power supply which is still functional until I retired it.

Is there a reset or self test function on the HP 45 that might get this vintage calculator running again ?

I will give it to a collector if they will pay shipping.

Thanks, winespirit69
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02-26-2019, 01:51 AM
Post: #2
RE: HP 45 display malfunction
(02-25-2019 11:00 PM)winespirit69 Wrote:  HP 45 purchased 11/1/73 from Mich Tech Bookstore ~$400.
When powered on "all" display digits flash red 8's, decimal (currently at 2 digit accuracy) and
the "-" sign on the far left. I believe the display is fully functional (meaning no partial digits) as are all of the keys. After a period of time the display goes blank. If allowed to warm up the display goes blank more quickly. Otherwise this vintage calculator appears to be in "Very Good" condition. There is no corrosion in the battery compartment. All four rubber foot pads are in good shape as is the battery compartment cover. The original rechargeable battery was discarded years ago and I ran it directly on the power supply which is still functional until I retired it.

Is there a reset or self test function on the HP 45 that might get this vintage calculator running again ?

I will give it to a collector if they will pay shipping.

Thanks, winespirit69

There could be multiple issues. Anode driver failure, ROM failure, power supply not working properly. Hard to say without running some tests.

If the display chips and LEDs are functional, you could try running my replacement software with one of Haralds MultiCalc boards which will get it running again.

Other than that, I'd be happy to try and resurrect it :-)

cheers

Tony
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02-27-2019, 02:07 AM
Post: #3
RE: HP 45 display malfunction
Tony, thank you for your insightful response. I myself have moved on to using 11C / 12C / and 15C because I prefer RPN. Money is a little tight so I am looking to place my HP 45 in the hands of a collector or enthusiast who might appreciate it more than I do. If it worked I would keep it for esthetic purposes but I really don't wish to put any money into it. I might kick myself down the road. I will most likely list it, the case, user's manual, quick reference guide and ac poser supply on eBay with a note that there are people out there that can help get it working.
Thank you again for taking the time to respond.
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