The Museum of HP Calculators

HP Forum Archive 21

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Video of Ghost HP-11C keys on HP-12C
Message #1 Posted by Max Stone on 8 Apr 2013, 4:21 p.m.

While it's been documented before, I thought that a video showing the 'ghost keys' on a 1988 HP-12C (USA production) would be interesting. You can clearly see the HP-11C key legends as the light angle changes. BTW, the keys are definitely double moulded. Had a look with my son's 100X microscope and I can clearly see the 'shared' plastic border where the two plastic meet, while the blue text is clearly raised, printed over the key. While it appears the key legends are overpainted with this 'ghosting', it's definitely a characteristic of the moulding process.

Link to video is here: HP-12C Ghost Keys Video

      
Re: Video of Ghost HP-11C keys on HP-12C
Message #2 Posted by Harald on 8 Apr 2013, 4:41 p.m.,
in response to message #1 by Max Stone

The interesting thing is that both my 11c and 15c have 12c "ghosts".

            
Re: Video of Ghost HP-11C keys on HP-12C
Message #3 Posted by Michael de Estrada on 8 Apr 2013, 7:39 p.m.,
in response to message #2 by Harald

I can see the 15C ghosts on my 12C, but cannot see any ghosts on the 15C. The 12C is from 1987 and the 15C is from 1982.


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