HP-12C 1985 vintage repair

[pvanloon]

I have a HP-12C(serial #2512A03269) that I have had since 1985. It was sitting in my desk for several years, no batteries installed. Today I bought new batteries and installed them. This is what showed up in my window:

-8,8,8,8,8,P,8,A,8,8,
USER f g BEGIN GRAD D.MY C PRGM

I have attached a photo.

I am wondering if my calculator is beyond redemption. I hope it is not, as I very much appreciate it.

I have tried the clearing of memory - nothing. I even try to turn it off but it stays on with that stuff still in the window. It will shut off in time, but then when I hit the ON button I get the same stuff.    

[teenix]

(08-01-2019 12:44 AM)pvanloon Wrote:  I have a HP-12C(serial #2512A03269) that I have had since 1985. It was sitting in my desk for several years, no batteries installed. Today I bought new batteries and installed them. This is what showed up in my window:

-8,8,8,8,8,P,8,A,8,8,
USER f g BEGIN GRAD D.MY C PRGM

I have attached a photo.

I am wondering if my calculator is beyond redemption. I hope it is not, as I very much appreciate it.

I have tried the clearing of memory - nothing. I even try to turn it off but it stays on with that stuff still in the window. It will shut off in time, but then when I hit the ON button I get the same stuff.

It may have suffered corrosion or other mess internally or on battery contacts.

cheers

Tony

[rprosperi]

Does it flash "running" a few times prior to showing that display? If so, then it's running it's self-test, as this is the screen shown when it completes successfully. This is normally launched by holding down the [X] key, then press and release [ON] and then release [X]. Is it possible your [X] key is jammed down?

Also, try this: Remove your batteries and then short the 2 battery terminals together; you can use a small piece of wire or even a pair of scissors - any metal conductor. While shorting the terminals, press and release the [ON] key. Then re-insert the batteries. Amazingly this simple procedure sometimes succeeds in clearing a machine that is locked-up in some confused state.

Good luck