leejsmith
Cham Cham's Banana
- Joined
- Aug 11, 2017
- Posts
- 159
I spent the past few days working through this problem, but still not sure why it has no audio.
What I do know is the Z80 pin 22 WR is HIGH and the NMI (17) and INT (16) are low. all 8 data lines are stuck as well as address lines 8>15.
I have checked the 245 and 244 chips on the top and I can see they are passing the correct data when the other slots are working. I have removed these chips, tested them and put sockets in. All connections are ok.
Connections from the cartridge are also ok.
sdmrd looks good, but sdrom and sdrd0 also stop pulsing.
I ran the diagnostic bios with the m1 chip and it says z80 dead or expected was not the correct data.
I checked the as244 and 245 on the lower board. the ls32, ls139, ls257 x 2 and these are ok.
I have not checked the 6116 ram, but its ok with the other slots.
so when a cart is in slot 4, data and half the address bus just stop, but i am not sure what to check next.
What I do know is the Z80 pin 22 WR is HIGH and the NMI (17) and INT (16) are low. all 8 data lines are stuck as well as address lines 8>15.
I have checked the 245 and 244 chips on the top and I can see they are passing the correct data when the other slots are working. I have removed these chips, tested them and put sockets in. All connections are ok.
Connections from the cartridge are also ok.
sdmrd looks good, but sdrom and sdrd0 also stop pulsing.
I ran the diagnostic bios with the m1 chip and it says z80 dead or expected was not the correct data.
I checked the as244 and 245 on the lower board. the ls32, ls139, ls257 x 2 and these are ok.
I have not checked the 6116 ram, but its ok with the other slots.
so when a cart is in slot 4, data and half the address bus just stop, but i am not sure what to check next.