HP 45 display malfunction

[teenix]

(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