SaminVA
Well-known member
I am trying to get my second spare Star Wars board working and I could use some help. I had another thread started when I was working on my main board and in the process I was trying to use this board set for testing. This board started out completely dead but replacing the CPU and some of the RAM chips I got the board working but it still has problems. I know the AVG vector board works 100 % as it was tested on my working board set. It still has my original graphics glitch because the AVG chip is bad but it will get a new chip when I get the problem with the main board figured out. I also have a sound board problem, it too was totally dead but came back to life with a new CPU ,RAM and PIA chip. I now have sound and music but have no speech. I'll get back to that after the main board problem is fixed. Now for the main board problem. In game mode the attract mode runs but theirs no stars in the background. You can coin up a game but no stars and no tie fighters or death stars, nothing. You can only shoot endlessly into the black of space. As I said before I do have music and sound effects but no speech. In the video I have the sound board removed so I can have access to the main board. In test mode it's reporting a Bad Math RAM at 5H. I know the RAM is good, it's been swapped and tested in the other board. If I swap the RAM at 5H with 5F it still reports 5H as Bad. I am also getting Matrix Errors but I believe it's because something is keeping the RAM at 5H from working. I have searched this board as well as the Vector List and Google and found some problems close to the same and one almost identical but it was a 5F error instead of 5H but no solution was ever posted.
Here's what I know so far, all ROMs and Rams and PROMs are tested good, that includes the 4 PROMS at 7H,7J,7K and 7L. I have also replaced the socket and replaced the 74LS245 at 4H which is the Matrix Processor Data Selector with no change. Comparing the 2 RAMs at 5H and 5F as well as the 74LS245s at 4H and 4F with a logic probe the only difference is pin 10 on the RAM 5H and pin 8 on 4H are stuck low wile pin 10 on the RAM 5F and pin 8 on 4F are pulsing. This is as far as I have checked and I was wondering if anyone has any suggestions of what to check next. I have been looking over the troubleshooting guide but haven't figured out what you do even if you set the dip switches and perform a test I don't understand what is suppose to happen? Someone needs to write a Star Wars troubleshooting guide for dummies.
Here's what I know so far, all ROMs and Rams and PROMs are tested good, that includes the 4 PROMS at 7H,7J,7K and 7L. I have also replaced the socket and replaced the 74LS245 at 4H which is the Matrix Processor Data Selector with no change. Comparing the 2 RAMs at 5H and 5F as well as the 74LS245s at 4H and 4F with a logic probe the only difference is pin 10 on the RAM 5H and pin 8 on 4H are stuck low wile pin 10 on the RAM 5F and pin 8 on 4F are pulsing. This is as far as I have checked and I was wondering if anyone has any suggestions of what to check next. I have been looking over the troubleshooting guide but haven't figured out what you do even if you set the dip switches and perform a test I don't understand what is suppose to happen? Someone needs to write a Star Wars troubleshooting guide for dummies.