An HP-48G opened.


The reason I opened this calculator is to see how a Charlemagne model can be opened and how it was build. I chose this calculator because it was broken. It wouldn't start up with a fresh set of batteries. This was also some damage visible caused by spilling paint or Tipp-ex over the keyboard.

HP48G_01 HP48G_01

These pictures show the situation, after some cleaning, for the outer and inner side.

The HP-48G is NOT easy to open. A few nice documents about opening an HP-48G can be found on the internet and are linked at the bottom of this page.

After a lot of struggling the calculator was open.


The pictures above show both halves of the housing. The left picture is the most interesting one. On top we see the connector and two LED diodes, one transmitter and one receiver. The three chips on top are the saturn processor in the middle with two display driver chips on its side. On the bottom we find two memory chips.

The backside of the calculator is shielded by a metal plate. On this plate we find the gold colored circular shaped buzzer.

To reach the keyboard, the printed circuit board has to be removed. This board is attached with six twisted metal clamps. The clamps press the board with foam stripes towards the LCD display.


The metal plated is fixed by a lot of heat stakes. The heat stakes have to cut.

The keyboard is build in the same way as the keyboard of the Pioneer series. Both sides of the keyboard foil of this calculator are shown in the next pictures.


Conclusion: It is build in the same way as the Pioneer Series.



Charlemagne repair related links: