HHaase
Active member
This is an intermittent problem. Sometimes I can play for hours with everything running just fine. Then, sometimes, all the enemies will suddenly get much much faster. Other times, they just stop moving totally. Bullets, mine and theirs, follow suit..... I.E. when THEY get fast, the bombs/bullets get fast. When they stop, the bombs/bullets stop moving.
However, the player ship speed stays normal in both cases, as does the starfield backdrop. Meaning that when the enemies stop, I can still move my ship back and forth and the starfield still moves. If I don't have 2 shots in the air at the time, I can still fire (with sound) until there are two shots visible...... but then they would just appear where my ship is but never move upward at all. I can reset the game using either the slam switch or the test switch, and it goes back to operating normally.
So, my assumption is that there's something wrong in whatever sets the pace of the game speed but not that of the processor speed.... so for now I'm going to rule out the system clock. I suspect that one of the Z-80's is likely the problem, as the graphic images are unaffected, neither is the sound, nor the control inputs. I could just replace all 4, and IF that's the problem I'd be done with it, but I'd rather know a bit more about what actually controls the speed of the enemies, as if my guess is wrong I'll have to start tracing the problem in further detail.
As a side note: Anybody that can explain to me if there's any pattern to the chip locations on the board. I have the schematic, but how can I determine which chip is 4E or 10P or 8M if there's no markings on the board?
-Hans
However, the player ship speed stays normal in both cases, as does the starfield backdrop. Meaning that when the enemies stop, I can still move my ship back and forth and the starfield still moves. If I don't have 2 shots in the air at the time, I can still fire (with sound) until there are two shots visible...... but then they would just appear where my ship is but never move upward at all. I can reset the game using either the slam switch or the test switch, and it goes back to operating normally.
So, my assumption is that there's something wrong in whatever sets the pace of the game speed but not that of the processor speed.... so for now I'm going to rule out the system clock. I suspect that one of the Z-80's is likely the problem, as the graphic images are unaffected, neither is the sound, nor the control inputs. I could just replace all 4, and IF that's the problem I'd be done with it, but I'd rather know a bit more about what actually controls the speed of the enemies, as if my guess is wrong I'll have to start tracing the problem in further detail.
As a side note: Anybody that can explain to me if there's any pattern to the chip locations on the board. I have the schematic, but how can I determine which chip is 4E or 10P or 8M if there's no markings on the board?
-Hans
