Hyper Olympics 84 Repair Logs
CPU board tested good by substitution. Replaced bad 504 and 082 custom Konami chips. Board now runs but has corrupt player graphics. Signal DM7 (pin 11 of H3) is stuck low causing the corruption. The chip at H3 and the chips it drives at J4 and H4 are all good. The CLK4 signal is incorrect. A check of a good board shows pulses in groups of 3 and the bad board shows pulses in groups of 2... Replaced a bad 74LS20 at location E16 to finish the repair.