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Early 12C calculator with blue display ???
07-14-2022, 08:14 PM
Post: #1
Early 12C calculator with blue display ???
I picked up this odd looking 12C with a blue display. I’m not sure if this has an unusual display or if the display is just delaminated. The background is a local electronics recycler here is Boise got around 12 early 11Cs and this one 12C . All of the 11Cs were from 1981 and in excellent condition and were also all defective. I assume they were returns at one point to the HP facility in Boise. This 12C is not working. I’m just curious if this could be a prototype or experiment. I opened it up and the inside looks like any production calculator.


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07-15-2022, 12:45 AM (This post was last modified: 07-15-2022 05:13 PM by Marcovecchio.)
Post: #2
RE: Early 12C calculator with blue display ???
Perhaps the LCD is from an early batch, made by another supplier. LCD color and behavior is greatly determined by the polarizer filters glued on the front and back, the inner glass is just transparent.

I think this display could be turned into a regular LCD by replacing the polarizers, and any voyager LCD could be made blue like this, with the correct polarizer.

Recently, I managed to fix and enhance an HP48G blue LCD with gray polarizers, making it into a high contrast black one, just like the ones on HP49g. The only difference were the polarizers!
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07-15-2022, 04:11 AM (This post was last modified: 07-15-2022 04:50 AM by HP-12C.)
Post: #3
RE: Early 12C calculator with blue display ???
Have never seen a screen turn completely blue before but can be the screen is damaged from the sun or something has pressed against it hard.
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07-15-2022, 06:42 AM
Post: #4
RE: Early 12C calculator with blue display ???
(07-15-2022 12:45 AM)Marcovecchio Wrote:  Recently, I managed the fix and enhance an HP48G blue LCD with gray polarizers, making it into a high contrast black one, just like the ones on HP49g. The only difference were the polarizers!

Not to derail the thread, but do you have any pointers on what you used to accomplish that? I'd love to "upgrade" my 48GX!
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07-15-2022, 05:05 PM
Post: #5
RE: Early 12C calculator with blue display ???
Must be very early, yes.
Due to https://www.hpmuseum.org/collect.htm#earliest
the earliest serial by "now" (don't know when this reference was created or updated when newer earliers were found) is 2031.. whilest yours is 2030A..
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07-17-2022, 12:36 AM
Post: #6
RE: Early 12C calculator with blue display ???
(07-15-2022 06:42 AM)drbarnack Wrote:  Not to derail the thread, but do you have any pointers on what you used to accomplish that? I'd love to "upgrade" my 48GX!

Sure! I'll post a thread later with details. But it's just a matter of finding the correct polarizers and angles. Stay tuned. Smile
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