Re: Sounds like you've got it diagnosed . . . Message #4 Posted by Paul Brogger on 10 Dec 2003, 5:49 p.m., in response to message #3 by Brian Markey
. . . Now to fix it.
I have pulled out the rubber strip and bolstered it (from behind) with a piece of scotch tape, rolled up tightly lenghtwise, sticky side out. That's probably pretty crude, but what you want, I think, is a uniform, approx. 1/16" thick piece of sticky stuff behind the rubber to make it "sit up" better. (Sticky simplifies reassembly.)
Removing and replacing the PCB is THE most tricky part of the operation. Make sure you un-twist the six (IIRC) hold-downs in the proper directions (i.e., you don't want to put a full 180-degree twist in 'em, you want to reduce the twist to zero). Use a small, flat-nosed plier, and be careful not to scratch the PCB.
Clean any dust off of the LCD contacts (gold traces on the PCB, rubbery strip(s) with embedded conductive paths on the LCD itself) before putting it back together. Re-twist the hold-downs and test. (Don't take the rubber LCD strip(s) off of the LCD unless absolutely necessary -- sounds like it shouldn't be in this case.)
Folks who do this a lot have been known to build a "jig" that:
1. pinches the calculator front and PCB together,
2. doesn't short any PCB traces, and
3. leaves the keyboard and display free for testing.
(I've yet to build my own, but plan to use one of those yellow plastic ratcheting clamps from Home Depot.) The idea there is to be able to test the keyboard and LCD connections to make sure they're good before twisting the metal hold-downs again. I have pinched them together with my fingers while testing, but ever since my third hand was amputated, that's been kind of rough.
Good luck!
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