Moon Patrol - factory jumper for positive sync?

Jeff F

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Was doing a little research to see if there was a unused 74LS04 hex inverter that I could use to turn Moon Patrols negative sync into positive and I ran across this jumper...
MoonPatrol-sync.jpg


I'm assuming CPS is composite sync and HS is horizontal sync.

Looks like I can move the jumper from the left side of R3 to pin 6 of the 74LS00... which is right next to it on the PCB. Correct?

If so, it almost makes it as easy as the other Williams games... almost. :)
 
Yep, it worked.

But... I needed it to be negative sync so I don't know why I felt the need to work on this? Oh yeah... to waste a couple hours on basically nothing. That about fits my life... :rolleyes:
 
On the 74LS74, HS is wired to the Q output pin 5. You could cut the trace and jumper it to pin 6 Qnot. If you put it in a socket... then just lift 5 and jumper pin 6 over. You should now have negative sync.
 
On the 74LS74, HS is wired to the Q output pin 5. You could cut the trace and jumper it to pin 6 Qnot. If you put it in a socket... then just lift 5 and jumper pin 6 over. You should now have negative sync.

5 is /HSYNC.
6 is HSYNC.

2D:4 is /VSYNC

The circuit is giving you /HSYNC & /VSYNC == /CSYNC

Switching 2D:5 would give HSYNC & /VSYNC, inverting only one component of the sync, and really confusing the monitor..
 
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