TI Little Professor (1982) 28 SDIP Chip labeled CD4570A NL P M 8319 Philippines die labeled 0456-70A 18 buttons: 0-9, on, off, tables, level, +, -, *, / 9-digit LCD 1##+##=### Pic: http://www.datamath.org/Edu/Professor-82.htm PCB: http://www.datamath.org/Edu/JPEG_Professor_82.htm#PCB Manual: http://www.datamath.net/Manuals/LittleProf82_US.pdf Pin 2 Pin 5 Pin 7 Pin 10 batt + tables level off on Pin 4 7 8 9 / Pin 1 4 5 6 x Pin 26 1 2 3 - Pin 3 0 + 1 KP row 3 and LCD digit 3 2 KP column 1 3 KP row 1 and LCD digit 2 4 KP row 4 and LCD digit 2 5 KP column 2 6 LCD digit 1 7 KP column 3 8 LCD digit 1 9 LCD little professor 10 KP column 4 11 battery - 12 battery + and KP row 5 13 LCD segments B and G 14 LCD segments A and F 15 LCD digit 4 16 LCD digit 4 17 LCD digit 5 18 LCD digit 5 19 LCD operation symbol 20 LCD operation symbol 21 LCD digit 6 22 LCD digit 6 23 LCD digit 7 24 LCD digit 7 25 LCD digit 8 26 KP row 2 and LCD digit 3 27 LCD segments C and E 28 LCD segments D and DP digits 8 7 6 5 4 3 2 1 - - - - - - - hat | | | | | \ . / | | | | | - | | | | | | eyes - - - - - - - - - - moustache | | | | | / . \ | | | | | - | | | | | | - - - - - - - 1 2 3 4 * * * * * (diff level) (operation) (scoring stars) segments A A A A A A A B F B F B G F G A F B F B B F B F B F B G G E B A G G G G G B E C E C C D C A E C E C B E C E C E C D D D D D D D C D P P P P P P P LCD signals pin 28 pin 27 pin 14 pin 13 25 difficulty level 2 difficulty level 1 digit 8 both segments 24 difficulty level 3 digit 7 segment E digit 7 segment F digit 7 segment G 23 digit 7 segment D digit 7 segment C digit 7 segment A digit 7 segment B 22 difficulty level 4 digit 6 segment E digit 6 segment F digit 6 segment G 21 digit 6 segment D digit 6 segment C digit 6 segment A digit 6 segment B 20 operation center left bar operation upper dot operation upper diagonals 19 operation lower dot operation lower diagonals operation right 1/2 of + operation center right bar 18 scoring star 1 (left) digit 5 segment E digit 5 segment F digit 5 segment G 17 digit 5 segment D digit 5 segment C digit 5 segment A digit 5 segment B 16 scoring star 2 digit 4 segment E digit 4 segment F digit 4 segment G 15 digit 4 segment D digit 4 segment C digit 4 segment A digit 4 segment B 26 equals sign digit 3 segment E digit 3 segment F digit 3 segment G 1 digit 3 segment D digit 3 segment C digit 3 segment A digit 3 segment B 3 scoring star 3 digit 2 segment E digit 2 segment F digit 2 segment G 4 digit 2 segment D digit 2 segment C digit 2 segment A digit 2 segment B 6 scoring star 4 digit 1 segment E digit 1 segment F digit 1 segment G 8 digit 1 segment D digit 1 segment C digit 1 segment A digit 1 segment B 9 scoring star 5 (right) hat brim, moustache down hat top, moustache up hat without top or brim, glasses, mouth