Does the monitor chassis have a jumper to select either 15k or 24k? I think it does. Are you changing that setting to match the PCB?
http://forum.arcadeotaku.com/viewtopic.php?f=4&t=6623
http://forum.arcadeotaku.com/viewtopic.php?f=4&t=6623
Hey John
Done this before, changed position of the molex to 24khz and back to 15khz no change.
What i have read is that some Bootleg games have this problem with sync on astro city dont know if thats a fact
rgrds