Schematic
Schematic of the Casio Personal-8 of 1975: Hitachi HD3679 single chip driving an NEC LD8120 tube directly, Fuji MPS 0606 converter giving -6, -14, -22 and -29 V and 1.4 V AC filament from 3 V, 1.67 kHz scan.
VF1 FUJI 3 1.4VAC MPS 0606 6 14 8• 4 VF2 220p 10 100K 5 Sa Sa NEC LD8120 19 150K 8 DIGIT VACUUM FLOURESCENT 6 Sb Sb DISPLAY MODULE 1 18 3V V–14 –tip 10 33 -- Sc Sc 22K 16V 17 10V 2• 7 a -- Sd Sd 1.5V 10 V–6 16 f b POWER 16V g Se Se 220p 8 15 e c V–14 22n Sf Sf p 13 d 9 Sg Sg V–22 12 ?V 330 22n Sp Sp 150p 20 D9 D1 V–29 Hitachi V–22 2 HD3679 8• 0.022 7 100K ØD8 21 1M n.c.: 11 ØD7 22 V–14 ØD6 23 ØD5 24 3• 100K 3 ØD4 0 1 2 3 4 5 6 7 25 1 ØD3 each 26 5 key 8 9 AC C % ÷ 2 ØD2 27 4 = DP + – ØD1 11 28 2 8 9 1 V–29 V–29 3 4 5 6 7 8 9 10 V–14 V–6 • Digit scanning is LSD first. • Number cycle is 1.67 KHz (0.6mS), with additional non-displaying “fast scans” every 8-or-so number cycles. • Capacitance in microfarads unless otherwise specified. • This drawing based on unit with Serial No. 4109659. • 2001 May 05: Initial drawing / bhilpert. 2020 Feb: Format updates / bh. Casio Personal-8 Calculator Page: 1 / 1 Printed: 2020 Feb 11