This one has me scratching my head. Can't seem to make sense of this. Here are the details.
1. I am de-jammatizing a hacked up Robotron with a G07 as the monitor.
2. I have a new repro harness and the video for Williams games is positive hsync & vsync. I can't get the picture to sync on the G07 using the 6 pin header. I first thought maybe a monitor problem in the sync circuits. Everything seemed to test ok in those circuits. I examined the hacked JAMMA harness and noticed it was using pin 7 of the video connection on the Williams CPU board as csync but was connected to the 3 pin header on the G07 for negative csync. So I tried to hook it up to the negative sync 3 pin header and was able to get the picture close, but was never able to get it to lock horizontally. I would always get some sort of roll -- sometimes fast, sometimes slow. This again, pointed my in the direction of the monitor.
3. So I hooked up a WG who knows what (not sure the model) monitor to the Robotron board and tried the normal (separate h+v) positive sync and it was rolling all over the place. Moved the sync to the negative header and bang -- had a stable picture. Only issue was I could not adjust the horizontal position enough to make it center. No biggie, just testing.
4. Thought the G07 might have a sync issue. Pulled it and put it in my Joust out in the garage (with the positive 6 pin header) and had a stable picture. So maybe it just has an issue with the neg sync circuit. Who knows.
5. So this is leading me to the Williams CPU board only putting out negative sync.
Here come the questions.
Q1. I did some searching here and found that the CPU board does put out csync at pin 7 of the video connection. Which would be positive csync correct?? And to get negative csync you would cut/remove W1 to make it negative?? My W1 is not cut, but somehow only syncs to negative sync (on the WG monitor). Do I have this correct? Or how else can this be modded to put out negative sync?
Q2. To test if the CPU board is really the culprit, can I pull the Joust CPU board and drop it in the Robotron without any chip swap?
I have spent 6+ hours on this issue and maybe making some progress now, but this moving monitors and swapping wires is driving me nuts and I not sure if the G07 is ok since I can't get it to sync via the negative. So, what y'all think.
1. I am de-jammatizing a hacked up Robotron with a G07 as the monitor.
2. I have a new repro harness and the video for Williams games is positive hsync & vsync. I can't get the picture to sync on the G07 using the 6 pin header. I first thought maybe a monitor problem in the sync circuits. Everything seemed to test ok in those circuits. I examined the hacked JAMMA harness and noticed it was using pin 7 of the video connection on the Williams CPU board as csync but was connected to the 3 pin header on the G07 for negative csync. So I tried to hook it up to the negative sync 3 pin header and was able to get the picture close, but was never able to get it to lock horizontally. I would always get some sort of roll -- sometimes fast, sometimes slow. This again, pointed my in the direction of the monitor.
3. So I hooked up a WG who knows what (not sure the model) monitor to the Robotron board and tried the normal (separate h+v) positive sync and it was rolling all over the place. Moved the sync to the negative header and bang -- had a stable picture. Only issue was I could not adjust the horizontal position enough to make it center. No biggie, just testing.
4. Thought the G07 might have a sync issue. Pulled it and put it in my Joust out in the garage (with the positive 6 pin header) and had a stable picture. So maybe it just has an issue with the neg sync circuit. Who knows.
5. So this is leading me to the Williams CPU board only putting out negative sync.
Here come the questions.
Q1. I did some searching here and found that the CPU board does put out csync at pin 7 of the video connection. Which would be positive csync correct?? And to get negative csync you would cut/remove W1 to make it negative?? My W1 is not cut, but somehow only syncs to negative sync (on the WG monitor). Do I have this correct? Or how else can this be modded to put out negative sync?
Q2. To test if the CPU board is really the culprit, can I pull the Joust CPU board and drop it in the Robotron without any chip swap?
I have spent 6+ hours on this issue and maybe making some progress now, but this moving monitors and swapping wires is driving me nuts and I not sure if the G07 is ok since I can't get it to sync via the negative. So, what y'all think.

