Most of these Cinematronics/Leland games use the same main board with different game-specific top boards.
Top PCB (for Off-Road)
-------
PCA # 81-18002-2
PART # 80-18002-01
|-\ /-----------------------------------|
| \-------/ AD7524 LM324 J8 |
| AD7524 AD7533 LM324 J7|
| AD7524 J9 LM324 |
| AD7524 LM339 |
| AD7524 LM339 |
| AD7524 J6|
| U75 U82 |
| U9 16MHz U44 76C88 U74 U81 |
| 80186 U43 76C88 |
| U8 U42 ADC0820 J5|
| U7 U59 |
| U6 71054 U58 |
| U5 U15 U27 71054 U57 J4|
| U4 U14 U26 U56 |
| U3 U13 U25 |
| U2 U12 U24 U55 U68 J3|
| Z80(2)76C88 76C88 U54 Z80(1) |
| J1 BATT DS1221 J2 |
|-----------------------------------------------|
Notes:
80186 - Siemens SAB80186-1-N x86 CPU. Clock input 16MHz, runs at 8MHz with an internal /2 divider.
Z80 - Master(1) & Slave(2) Zilog Z0840006 CPU. Clock input 6.000MHz [both, 12/2]
76C88 - Goldstar GM76C88-10 8kBx8-bit SRAM, equivalent to 6264 etc
BATT - 3.6V AA Lithium Battery. Connected to the 2x 76C88 SRAMs just above U59. Used to hold the book-keeping data and high scores.
Not required/essential for normal operation.
--SNIP--