Quoted from SteveNZ:
I checked all 4 lines that are connected to the dips, I get 4.98v when the dip is open and 0v when the dip is closed. I also checked the image in the 27C256 and it looks to me that ROM 0 is the first one in the list. I did this in case ROM 4 was accidentally written to the 27C256.
Is there any chance that when all 4 addresses are low it does not select the first chunk, as in should it be some other combination of address pins?
After thinking about it, I realized that the 27256.bin file was too long. It had 17 ROM images instead of 16. Perhaps the burning software you're using got confused by the extra bytes and wrote the image wrong. So I've removed 16-edit_cmos from the 27256.bin image. You can still find the edit_cmos test in the zip file as a standalone 2K image if you want to use it.
Please download the latest version and try again.
Quoted from SteveNZ:
Unfortunately I can't report back on very much yet. I have 2 System 6 boards that will not pass the LED test, so I am stuck at the BUS (ROM 0) test. given my issue above with selecting ROM 0, I burnt a 2716 with ROM 0 for testing.
While I'm here, I should check some things:
I understand that these test ROMs are designed to be used with the boards in the game. Can I use the ROMS with the boards on the test bench instead?
Do the ROMs, including the BUS ROM, only work correctly if the driver board is connected?
On 1 of my boards Pin34 on the CPU is high but J1 is installed and R4 is removed and a 6808 is installed - so I need to figure out what is going wrong there.
On both System 6 boards I have some address lines that are not as per your expected conditions. I'll look to trace those lines through the board to see where the problem lies.
You should be able to use the ROMS out of the game and on the bench. However, without any of the displays and switches etc you will not be able to do much with the latter tests. Since the earlier ones dont require any input from the user and results are only displayed on the LEDs they can be of use while on the bench.
00-bus does not initialize any PIAs and should run without the driver board connected. The rest of the tests each initialize all PIAs and technically should require the driver board, but I dont think the CPU will lock up trying to write to a PIA that isn't there so you should be able to get away with leaving the driver board disconnected. I will put an MPU board on the bench and verify.
For Boards with 6808 processor (J1 Installed and R4 Removed) you will require a RAM chip in IC13 for for normal game operation. Test ROMS 00-bus through 06-ram3 do not require any RAM or CMOS whatsoever (aside from the obvious RAM/CMOS they are testing). So as far as software goes, it shouldn't matter what pin 34 is doing, or what CPU chip you have, or whether you have any RAM installled at all. The test ROMs should still run.
The CPU chip itself may have something else to say about that. I'll see if I have a 6808 around and put it in a benched board without any ram and see if it can still run the tests.