Sucessful repair of HP32SII


My trusty 32SII developed a display problem; instead of digits, the LCD would show rectangular blocks instead. I figured I would buy a new one, so I went to my local office supply store and was amazed that they no longer carried it; I was even more amazed to look on the web and see that it was discontinued! One poster on got it right when he/she called it "The Cadillac of Calculators."

So, I repaired it, as follows:

1. Open case.

A. Apply slow, even pressure with a flat head screwdriver around the side seam, gently trying to pry the case apart. There are several plastic pin-in-socket ultrasonic welds all over the bottom of the case, and most of them will yeild without damaging the pin or socket given gentle and slowly-increasing presssure.

B. Pull hard on the four snap fittings at the top (under the battery door) to undo them.

2. Using a pair of needle-nose pliers, un-twist the metal tabs sticking out from under the circuit board.

3. Remove the circuit board.

4. Using tweezers, remove the two rubbery connecting pieces from the top and bottom of the display. (These are anisotropic conductors: if you tilt the display under the light with them removed, you can see the connecting pads on the LCD.)

5. Clean the rubber pieces, the display, and the circuit board pads using shop air at low pressure.

6. Replace the rubber pads.

7. Replace the circuit board.

8. Re-twist the metal tabs to firmly compress the rubber pieces.

9. Put batteries in the calculator and check to make sure the display problem is solved.

10. Try fitting the case back together. If any of the plastic pins don't fit in the slots, cut them off (if only a few) or shave them down (if many) until they fit.

11. Put the case on, forcing all the remaining pins into the slots, and re-do the snap fittings under the battery case.

You now have a working HP 32SII. The pressure-fit of the pins into the sockets is tight enough that there is no need for any glue: once you shave or cut off any offending pins, the case fits right back together and stays closed by pressure fit.

Now, time to get to that thermo homework...



You sure went to a lot of trouble since all you needed to do was to hold down the sqrt and E+ keys, then press C. You would have seen MEMORY CLEAR and you would have been done. It's in the back of manual under "Testing calculator operation".

BTW, if you really need to open one, there is a safer and better way to do so already in the Museum:

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