Spec of dust in a 16C LCD screen



I have a 16C which is in perfect condition except for having what looks like a small spec of dust inside the screen. Has anybody been in this same situation with a 16C or one of its sibling models, and found a way to solve it? I really don't want to take the calculator apart, because I remember doing a little bit of research, and it seems that these models were not assembled with disassembly in mind, and the calculator is kind of special (it belonged to someone who worked at Los Alamos in rocket propulsion if I remember correctly.)



Edited: 15 Oct 2009, 2:03 a.m.


Buy a can of compressed air. Remove the feet and the four screws on the back. Remove the back. Be careful not to lose the two tiny springs used for ESD protection.

Blow the sides of the LCD panel from the inside. Do it until the dust leaves!

Short bursts of air not a prolonged burst as the air is cold when it decompresses and may cause condensation on the inside Clear LCD protection lens which when dry may leave evaporation marks.

If you have trouble getting the feet back on purchase some THIN double sided tape and cut to size. Reapply the feet.

Cheers, Geoff

Edited: 15 Oct 2009, 2:42 a.m.


Hi Geoff,

Thanks for your very detailed explanation. I had the notion that even removing the back of one of these calculators was a destructive process to some degree. I'm glad to know I was mistaken. I will first try Jimi's approach, and if that doesn't work, then I will do it your way. I'm sure either way it should work.

Out of curiosity, since you sound very confident about this procedure, I assume you have performed it before. Did you do it on a 16C, or in one of the other models?

Many thanks,



I have had some luck in the past by charging up some fabric or paper with static electricity. You know, rub it on your pants or something. Anyway, then brushing the display, and it will sometimes "walk" the dust spec off the display. Certainly beats opening it up if you can get away with not.


Hi there,

Thank you for pointing this out, Jimi. Actually I had thought of this before, but I was a little leary of doing something like it just in case the static electricity is enough to damage the calculator (maybe I'm being too paranoid?) I think I might try your idea first, and then try Geoff's approach if necessary. First I need to make sure that by doing things your way I won't damage the calculator.



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