Re: Casio 121

From: Rick Bensene
Email: r i c k b (at) b e n s e n e (dot) com


More than likely, the Nixie tube anode driver transistor has failed for the 2nd digit. Schematics for this machine aren't available - Casio has them, but will not release them to the public. If you can get the part number off of one of the other anode drive transistors (there will be 12 of them), you should be able to find an appropriate replacement...most of these old machine used Hitachi 2SB and 2SC-series Japanese Silicon and Germanium transistors, and many of these have current-day replacements available. Good luck, Rick Bensene The Old Calculator Web Museum http://oldcalculatormuseum.com Beavercreek, Oregon