LogicDart display issue

[Gene Dorr]

I have an HP LogicDart, and recently noticed that the center of the display has started to darken (about 3-4 cm in diameter), and a small bubble (about 2mm in diameter) has started to form in the very middle. The individual pixels don't seem to be affected. It hasn’t experienced any trauma, or sat in direct sunlight, so I am having trouble accounting for this. I thought maybe I could get another — perhaps a non-working one, but with a good display — and transplant the display to mine. To my surprise, when I searched for LogicDarts on eBay, I found 5 of them — and 4 out of 5 exhibit the very same display darkening. Is anybody else out there with a LogicDart having this issue? Any ideas what's causing it?

I recall reading that HP used a different vendor for the LogicDart display than the one(s) they used for the 48 (and descendent) calculators — anybody know who that vendor was, and whether there’s any history of this apparently age-related decay?

[rprosperi]

Usually, at least for calculators, the darkening display is caused by exposure to extensive heat and/or moisture, even something simple like being stored in a cabinet next to a radiator. I'll ask Jake Schwartz, who owns a LogicDart, about his experience.