Adler 81CS EC41 Handheld Calculator

A handsome Adler 81CS designed by Adler aka T-A Vertriebs-GmBH Numberg/Germany, but made in Japan with serial number 72261047. This calculator uses a Toshiba HD37350 calculator chip. The only external components needed is a VFD display powersupply.  The VFD display is a flat rectangular design  with the markings on the back : itron FG95A1  Japan JDA.

Adler has made great effort in making this calculator as slim as possible, the electrolytic capacitors are all mounted near the edge of the PCB with a cutout to accomodate the major bulk of the capacitors.

Quite a bit of manual soldering work in the manufacturing in connecting up the battery terminals and DC input with wires to the PCB.

Note: To open the calculator, remove the battery cover, at the top edge of the case you will see two slots, insert a small flat blade screw driver in there and twist gently, then gently work down toward the other end of the case always using a twisting action with the screw driver. However when I first got the calculator I was in a hurry to open it and did not discover the hidden slots behind the battery cover, the result is that I cracked the brown half of the casing which luckily was repaired successfully with epoxy glue. Since then I have been able to open the case a few times without any damage.

Adler 81CS Calculator with green VFD display
Note the green display filter.

Space saving layout of electrolytic capacitors in
the Adler 81CS Calculator.

The use of a complete calculator on a chip -
Toshiba HD3735D make for a clean PCB layout.

The VFD display has uneven brightness
among the digits.