Hi,
  I've managed to get a calculator LCD hooked up to a PIC16F917 - it works
fantastically well, but I'm having trouble getting enough pressure applied
evenly across the elastomer (zebra-strip) connector. The plastic I'm using =
to
compress the display against the PCB seems to deform far too easily...

  I've also picked up a pair of "Taksun TS-268" calculators, but these use a
completely different connector system. The connector itself is a plastic
sheet, with carbon (they're black - carbon is the most likely candidate)
contact strips inside the plastic. These carbon strips are open at both ends
and "somehow" attach to the PCB and the LCD glass. Both sides are held down
with Sellotape.

  Simply pulling these connectors off only serves to rip the carbon coating
off onto the PCB. I've demonstrated that fact by trying to remove the keypad
connector, which is the same type as the LCD connector. I guess I need to
heat these contacts (?) to loosen the bond with the PCB and get the carbon =
to
remain on the plastic strip, then use some form of conductive adhesive to
stick it onto a new PCB. Any comments?

  It looks like I could - at least in theory - remove the connector strip
from the LCD glass and use an elastomer (Zebra Strip) connector instead.
Which leaves me with one problem - getting a connector that's long enough!
Any suggestions for sources of either very long (1ft or so) pieces of the
stuff that I can cut down, or pieces no less than 55mm long would be
appreciated. UK-based would be even better. Seems the connectors are pretty
hard to find - I haven't seen them in the Farnell or DigiKey catalogues.

  I'm also trying to find a way to isolate the IC from the rest of the PCB,
so I can connect the bare display up to a PIC, by way of the existing PCB
(which already has the connector strip attached to it). Seems hacksawing the
board would be the best option, but that carries the risk of damaging the
connector. Same applies to tinsnips; the board is a really badly made FR-2
(SRBP) thing -- read: incredibly cheap. Getting the black "goop splat" from
the CoB chip off is also going to be fun...

  These things are currently sold in just about every "Everything =A31" type
shop I've seen, so getting more isn't really a problem. Just that even at =
=A31
each, it all starts to add up if you ruin 10 or 20 displays just to get one
usable LCD :)

  Nice thing is, it uses the same LCD pinout (and I assume controller chip,
based on the way the tracks are wired) that the last calculator did.
Difference being, this one has the piezo sounder output wired up. The beep =
is
truly annoying...

Thanks.
-- =

Phil.                              | Acorn RiscPC600 SA220 64MB+6GB 100baseT
philpem@dsl.pipex.com              | Athlon64 3200+ A8VDeluxe R2 512MB+100GB
http://www.philpem.me.uk/          | Panasonic CF-25 Mk.2 Toughbook
... Don't believe in astrology. We Scorpios aren't taken in by such things.
-- =

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