Schematic
Lloyd's Accumatic 55 Calculator: Reverse-Engineered Schematic
Schematic of the Lloyd's Accumatic 55 (also labelled EH-8715) pocket calculator with a nine-digit fluorescent tube.
Schematic
Schematic of the Lloyd's Accumatic 55 (also labelled EH-8715) pocket calculator with a nine-digit fluorescent tube.
3 8• 150K L9 L6 Sa Sa FUTABA 9-CT-04 20 3 ~3VPP 9 DIGIT VACUUM FLOURESCENT R4 Sb Sb DISPLAY MODULE 5 4 R8 23 DCT-02 R14 Sc Sc –22V 24 L3 a 6 1 Sd Sd 6V 2.7K 25 50V f b +tip 33 1 L2 g C711 Se Se 10V 22K 0.47 26 7 e c C1211 2 50V 9 L10 4• Sf Sf p 27 d AA 4.7 200K 30K R2 50V Sg Sg 28 POWER [nv]-17 8 220 V–15 V–15 R12 14V 4.7 Sp Sp 19 470p[nc] 9 50V 2 D9 D1 V–29 L4 L5 L7 L8 R10 R9 R7 R6 R5 V–29 50K Rockwell 9• V–15 A1241PA 150K ØD9 38 n.c.: ØD8 41 1,5,6,7 37 10,11,13,14,18 21,22,29 ØD7 8 36 7 8 9 √ M EX KC1 39 2 40,42 ØD6 35 each 12 key 4 5 6 = % KC2 ØD5 1 34 15 ØD4 1 2 3 ÷ x^2 KC3 33 3 5 ØD3 16 32 C . 0 + – 1/x KC4 6 4 ØD2 31 Notes 12 8 9 10 11 7 ØD1 30 • Capacitance in microfarads unless otherwise specified. 4 17 V–29 V–15 V–15 • Power supply switching F is 9::11µS / ~100KHz. • Number cycle is 3.3ms / 300Hz. • Based on unit with Serial No. 8-19895. IC in this unit datecoded 7448. Unit also labeled as Model EH-8715. • 2020 Feb: Initial drawing / bhilpert. Lloyd’s Accumatic 55 Calculator Page: 1 / 1 Printed: 2020 Feb 14