|On calculator preservation (LCD darkening, pouches...)|
Message #1 Posted by Marc Ferrer (France) on 3 Dec 2012, 5:37 a.m.
This post is slightly off-topic since not directly linked to HP. I'd like to share some experience and eventually get some advice from you fellow collectors, so here it is :
Yesterday, I pulled out most of my calculator collection from its boxes. Besides the pleasure, I wanted to check a particular machine : a few years ago my Sharp PC-1211 LCD began darkening on its left side (a well-known problem specific to displays from that era). To my relief the phenomenon didn't scale up since last year, the computer is still usable. Alas, I discovered 2 other Sharps now suffering from the same disease : a PC-1251 and a PC-1245.
Then some facts surprised me :
1. The 3 machines are "attacked" at the LEFT side of the display. They were stored vertically, standing on their RIGHT side.
2. The problem shows up on two different generation displays : the earlier ones with a yellow filter (1211), and more recent, grey-looking ones (1245-1251).
3. It doesn't show up on the HPs, Casios and TIs I also own. Very brand-specific.
Until now I thought that only the early displays were prone to such failure, I was wrong. Now, considering that the machines were vertically stored, and darkening from the "up" side : could it be related to some fluid leaking at a "molecular" rate ? I remember having read that the sealing process of these displays is critical.
Anyway, my collector's purpose is to delay this darkening from growing up, if it's possible. I'm about to store the machines horizontally, but I fear that it makes the displays darkening from everywhere... Well, I'm not sure it has anything to do with gravity.
What do you think of that ? Surely there are chemists, physicists and process engineers among you all. I'd be very glad to hear from you. Even if deteriorating is irreversible, knowing why is always interesting.
I'll end this post with another bad discovery I made : some pouches (all brands, but especially the wallet-shaped and/or oldest ones) begin to exhibit the problem we all face with the "gummy wheels" ! Some of them get sticky when held in hand more than a few seconds, some are "oily". By chance I've always been storing then apart from the machines. It's the best we all can do.
Thank you for reading !