PCB Repair Logs Moon Patrol (Bootleg)
Moon Patrol (Bootleg)
Fix: The background, text and scrolling is handled by the bottom pcb marked MP-712D. Using the Schematics and a Scope I traced the problem back to a pair of 74ls173's @ 1D and 1E.
Problem: No sync
Fix: dead 74ls139 @ 2C on the CPU board MP-712B
Problem: No sound.
Fix: missing 1000uf 16v cap C21 and 3.579545 mhz crystal.
Problem: white blocks over moving sprites with horizontal lines through them.
Fix: Dead output of a 74ls08 @ 4D See pic 2
Board 2 (Blue bootleg)
Problem: Background layer is missing other than a green at the top and the red bottom layer. Layers do not move: game resets randomly.
Fix: Dead 74ls08 on the board labelled MP-712D which outputs all the background paralax scrolling data. Only pins 11, 12 and 13 get used 11 being the output. Fugitsu naturally
Board 3 (Green Bootleg)
Using good working set above I went through each layer and fix them.
Problem: Dead board, no clock on pin 6 of Z80
Fix. Output stuck high on 7417 @ L6 pin 12
Pic 4 and pic 5 show working input and output(inverted) on scope.
Problem: Blocky Graphics, program seems to be running but will crash after awhile.
Fix: Dead output on 74ls139 pin 12 (Fujitsu) All other out puts stuck high.
Problem: 5 out of the 6 enemy ships missing from top of screen in demo but you can still see the enemy firing. Other symptoms: Buggy splits apart(half buggy at bottom of screen) when jumping rocks when going up hill, as board warms up some sprites are split apart.
Fix: Bad 2114 ram @ K7
I must have raided this board at some point for the 32 and 256 bit proms @ 1F and 2H and a AY3-8910 on the sound board. All missing parts replaced with new ones. The high score save mod is based on the williams set so I reprogrammed my blue board to suit. Just a matter of reprogramming 6 roms and 1 prom.
And of course this is how all Moon Patrol's should look