Schematic
CDK C1HB Calculator: Reverse-Engineered Schematic
Schematic of the CDK C1HB desk calculator of 1977: a TI TMS1273 driving an Itron FG139A3 tube directly through 100 k pull-downs to -35 V, with a blocking-oscillator supply.
Schematic
Schematic of the CDK C1HB desk calculator of 1977: a TI TMS1273 driving an Itron FG139A3 tube directly through 100 k pull-downs to -35 V, with a blocking-oscillator supply.
12 DIGIT VACUUM FLOURESCENT 28 DISPLAY MODULE 24 a 100pF 25 23 b 26 22 c t a 47K 19 d f b g 18 e to V–15 e c p 10 more 16 f segmen d digits ts of all 0.02 1M 15 g digits 11 14 p 17 t 9 of 100K V–35 9 TMS1273NL 5 100K 4 V–35 3 10 A 2 100K 2 1 F ∑ K V–35 39 38 7 37 C 1 CE MT RM RV M+ M– += –= ¥ ÷ √ 100K 36 V–35 35 8 30 0 1 2 3 4 5 6 7 8 9 DP % 100K 29 V–35 27 6 V–15 13 of 100K V–35 D471 Notes POWER 0.01 • Capacitance in microfarads unless otherwise specified. 470 • Based on unit with Serial No. 453342. 10K ? 117VAC 10V IC in this unit is datecoded 7710. 10W –7V 10 • 1998 May 14: Initial drawing / bhilpert. 3.3 1.5K 16V 2020 Feb: Format updates/ bh. 560p 100 50V 0.5A 3.3 V–15 CDK-C1HB 850501-B ?V 50V Calculator V–35 Page: 1 of 1 Printed: 2020 Feb 1