The upper half of the calculator contains almost all of the components except
for the piezo "beeper" element, and there are no interconnecting
wires between halves.
The only obstacle is the snap-together "hooks" that David Holmes
refers to. These hooks are positioned near the [A], [F], [SIN], [1/x], [ON],
[+] and [.] keys (the one by the [.] key is a real bugger!). Refer to the
cutaway diagram below for details.
Key overlay here ___ \ ____________ \ | | ____________| ______ | | _ | | <--- Upper section. | | | | | ________________| | | |_| | | |___ Circuit board and other | | | components (affixed to | / | <--- Lower section. upper section) |/__ | Has a lip which | | | engages with metal Metal "hook" ---> | / | | "hook" from upper |/ | | section. | | | ________________| | | | |
To separate the two sections, you will need to push the lower section
out and down around the hooks. You can't do this from the outside because
the upper section hangs over the lower, so you have to go from the inside.
Luckily, the six slots in the keyboard (used by the separate user-overlays
that fit over the original overlay) near the [MTH], [ENTER], [blushift],
[NXT], [backspace] and [-], come in handy for this. These slots are not
exactly lined up with the hooks, but are close enough. You can insert something
in these holes (I used a jewelers screwdriver, flat head) at an angle that
is mostly down and somewhat out, to a depth of about 5mm, and come in contact
with the lower section. Push the lower section out about 2mm (this will
take a bit of force), while wedging something in the outside gap to separate
and hold the sections apart while working on the other hook positions (
a wooden matchstick works). I recommend starting with the [A] or [F] positions
first, working down whichever side you started with, then do the other side,
and leave the [.] position for later (there is no helpful slot there).
![]() |
![]() |
The two battery contacts which come through the case will need to go back through the case when the sections separate. The upper contact is hooked on a plastic boss, and needs to be freed from it. Just pop it off with your finger or a screwdriver. | |
(above the screen).
If you have freed all the hooks, the case should sort of hinge at the bottom
edge. This is due to the last hook (near the [.] key). Some careful twisting
and working of the sections should free this hook as well. You should now
be able to completely separate the two sections. I recommend at this point
that you take a pair of pliers and flatten that last hook so that it will
not hold next time. It is really not needed anyway, as the other six hooks
hold the unit together just fine.