Posts: 4
Threads: 1
Joined: Jan 1970
Thanks John, I suspected somthing like this
but what threw me was no signal when I dropped
my tester along the dark stripe.
Best regards nth
Posts: 1,153
Threads: 94
Joined: Mar 2006
I've only seen the "Zebra stripe" appearance in those from the earliest LCD calculators (not necessarily H-P) that I've disassembled. The most "zebra-like" examples I remember were strips of mylar (perhaps) with parallel conductive traces, wrapped around a squishy rubber core.
Later versions are rubbery (insulating) strips with conductors somehow embedded. In my experience, there isn't necessarily an obvious color coding to indicate which sides are conductive. Neither is it easy to determine with a multimeter, as the conductors themselves are tantamount to individual, fine wires, and it's hit-or-miss when you're trying to touch both sides of the thing with probes.
Also, while orientation is all-important, alignment isn't necessarily an issue for the later types. The pitch of the conductor grid being MUCH finer than that of the PCB/LCD contacts, when placed in approximation, correct connection of the various pads is virtually guaranteed, regardless of the left-to-right alignment of the conductor strip itself.
FYI