LJN Electronic Concentration Chip labeled TMS1000NLL MP0163 MS ^ 7927 die labeled MP0163 21 buttons: 4x5 grid + Change 1 switch: 1/2 Players 4 7-segment LEDs (2 left, 2 right) 3 LEDs - Error, Change, 4 Remaining Piezo buzzer TMS1000 pinout 1 R8 - button matrix row 3 2 R9 - button matrix row 4 3 R10 - button matrix row 5 (top) 4 VDD 5 K1 - button matrix column 1 (right) 6 K2 - button matrix column 2 7 K4 - button matrix column 3 + Change button 8 K8 - button matrix column 4 (left) + Player 1/2 switch 9 INIT - VSS 10 O7 - LEDs 11 O6 - segment G 12 O5 - segment F 13 O4 - segment E 14 O3 - segment D 15 O2 - segment C 16 O1 - segment B 17 O0 - segment A 18 OSC1 - OSC2 and 47pF cap to VSS, 47K resistor to VDD 19 OSC2 - OSC1 20 VSS 21 R0 - digit 1 22 R1 - digit 0 (left) 23 R2 - digit 3 (right) 24 R3 - button matrix row 2 and digit 2 25 R4 - button matrix row 1 (bottom) 26 R5 - Change button and Player 1/2 switch 27 R6 - piezo and 3.3K to VDD 28 R7 - piezo and 3.3K to VDD button matrix K8 K4 K2 K1 R10 Red Red Red Red R9 Yellow Yellow Yellow Yellow R8 Green Green Green Green R3 Blue Blue Blue Blue R4 Violet Violet Violet Violet LEDs R1 R3 R2 O7 Error Change 4 Remaining