a friend and i have been battling this tempest forever it seems. we are getting close, but it is still not right. starting out we had vertical collapse/played blind. we replaced the 1495 chips at A/B12 and A/B13 and two roms (111 and 117 iirc) and that got us a basically correct picture in test mode (baby steps). all the other roms tested ok.
the main problem now is that the game will simply not just start at power up. it will only start if you first put it in test mode and THEN switch over to game mode. on a couple of occasions it also spontaneously reset, though on our last power up it seemed to be functioning well once it started.
we tried swapping CPUs from a known working board but it did not solve it. this work is being done on my friend's test bench so we're certain it is the board (other tempest/black widow boards worked perfectly on it). i don't think the aux board/cable is a problem since it worked perfectly with his known working board.
any thoughts?
the main problem now is that the game will simply not just start at power up. it will only start if you first put it in test mode and THEN switch over to game mode. on a couple of occasions it also spontaneously reset, though on our last power up it seemed to be functioning well once it started.
we tried swapping CPUs from a known working board but it did not solve it. this work is being done on my friend's test bench so we're certain it is the board (other tempest/black widow boards worked perfectly on it). i don't think the aux board/cable is a problem since it worked perfectly with his known working board.
any thoughts?