Donkey Kong 3 Repair Logs
Symptom: Bad colors, garbage on screen, and screen scrolled.
Repaired broken legs on the horizontal adjustment pot and replaced a cracked vertical adjustment pot to fix the scrolling screen problem.
The video board had a corrosion problem on it. Replaced and socketed the 74LS373 at 3k, the 74LS157 at 3L, the 74LS157 at 3M, the EPROM at 3M, the EPROM at 3P, 74LS174 at 2N, 74S163 at 1N, and the 74LS267 at 1P. Cleaned the corroded pins on the PROM at 2N and replaced the bad socket. Now the video garbage problem was solved.
The bad colors would come and go when the board was tapped or flexed. Replaced a bad socket on the PROM at 1D on the CPU board then tested the game.
Symptom: Dead. Garbage on screen
The lower 8 address lines and the 8 data lines were garbled. Replaced a bad 74LS374 at 5F, 74LS244 at 7A, and 74LS240 at 2M to fix the problem.
Game would play but was missing some sounds. The RP2A03 at 5J showed no activity. The RP2A03 at 5J, and the EPROM for it at 6H tested good by substitution into another board. Replaced a bad SRAM IC at location 6F to fix the sound.