Flat Packs

I've only come across two electronic calculators that use flatpack IC's. In 1965, Victor Comptometer made an attempt to build a fully-electronic desktop electronic calculator, called the Victor 3900, that proved to push the state of the art just a little too far. The 3900 used round-case flat-pack IC's, with 22 leads, with spot-weld type technology used to connect the leads to the circuit traces on the circuit board. Unfortunately, the yields of the ICs were not very high, and there were lots of infant mortality problems with the chips dying once the machines were in the customer's hands. The machine, had it been successful, would have put Victor in the enviable position of making a massive jump in technology over the electronics used by anyone else at the time, and would have kept them ahead of the game for quite a long time. There's some information on the Old Calculator Museum website exhibit on the Victor 14-322 (a machine made significantly later using very conventional technology) at http://oldcalculatormuseum.com/vic14-322.html. In around 1970, the Casio AL-2000 (http://oldcalculatormuseum.com/casal2k.html), an early small-scale MOS IC-based programmable (in very limited form) calculator, used two 24-pin flat-pack integrated circuits made by Philco, in ceramic bases with gold lids and leads in the arithmetic logic unit. These are medium-scale devices, one of which (part number SC-1770) is a bit-serial adder adder, and the other chip (SC1771) is a complimenter IC, date coded in late 1968 to early 1969. The chips are surface mounted, again using some kind of spot-welding to connect the leads of the device to the traces on the circuit board. Rick Bensene The Old Calculator Museum http://oldcalculatormuseum.com