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HP-97 decimal point with ghost segment d
07-20-2020, 03:29 PM (This post was last modified: 08-01-2020 03:59 PM by AndiGer.)
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HP-97 decimal point with ghost segment d
I have here an HP-97 that always shows the decimal point with the digit d dim lit no matter where the decimal point is shown. No other strange behaviour.

I put another working main board into the rest of the calculator and all works ok but when I drop the main board into another known good HP-97 the ghost digits switches together with the main board to the other calculator.

It is the newer layout of the main board not contained in the service manual I once posted here.

I replaced C1 (2.2µF tantal capacitor) but that didn't change anything.

Any ideas?

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HP-97 decimal point with ghost segment d - AndiGer - 07-20-2020 03:29 PM

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