|HP-49G+ -- A Look Inside . . .|
Message #1 Posted by Paul Brogger on 18 Nov 2003, 4:33 p.m.
I was able to get my HP-49G+ apart and take a few pictures -- I thought I'd share them with you all.
The first one shows the two halves not quite fully separated, and the IR lens removed.
The upper, dark section is the inside of the bottom case half. The battery compartment is to the left, and the wires connect the AAA and backup batteries and a large electrolytic capacitor to the main board. The small silvery rectangle near the top is a piece of conductive foam serving as the negative battery contact with the PCB. The larger black circle is where the buzzer is mounted, the smaller concentric circles to its upper left are the reset switch (a springy rubber contact).
The lower half shows the front case half, with the LCD board on the left covered by self-stick foil-backed paper. (It's actually aluminum-colored -- it looks coppery in these pictures, for some reason.) The main (CPU/key/SD) board is on the right.
The IR lens is thin and flexible, and pops out easily, but would probably be hard to get back in without taking apart the case halves (at least partially).
The second picture shows the electronics a bit more closely. A capacitor is glued to the main board with a smear of red-orange goo, and the reset contact is some gold fingers interleaved near the blue jumper wire.
The main board connects to the LCD board via: 1) a mylar (?) ribbon that runs across the calculator, just to the right of the coppery-looking shielding, and 2) a series of solder connections along two edges of what looks like a rectangular extension of the LCD board, near the bottom of the picture.
The square black chip above & to the right is marked "ARM" -- the other two I haven't looked at too closely. There's another pad of conductive foam attached to the SD card slot assembly.
The third image shows most of the self-stick paper/foil backing peeled away from the LCD board, exposing what appears to be two blobs of black stuff apparently sealing two LCD controller chips on the board.
Also visible are the IR sender & receiver, and the USB mini-B socket.
This view gives a good idea how the thing is put together -- the two posts are what I drilled to free up the top end, and otherwise it's only a series of plastic tabs around the edge that lock into the bottom case. After "topping" the posts, the two halves snapped apart quite easily.
BTW, the black accent that surrounds the calculator face is actually applied, and the calculator front and "side bumper" are actually one piece. Don't pry upward on the black accent, as it's just decoration and won't get you anywhere.