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HP-12C 1985 vintage repair
08-01-2019, 12:46 PM
Post: #3
RE: HP-12C 1985 vintage repair
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

--Bob Prosperi
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HP-12C 1985 vintage repair - pvanloon - 08-01-2019, 12:44 AM
RE: HP-12C 1985 vintage repair - teenix - 08-01-2019, 03:39 AM
RE: HP-12C 1985 vintage repair - rprosperi - 08-01-2019 12:46 PM

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