tuco
New member
I have a sky soldiers which works perfectly apart form the graphics being a little corrupted.
On switch on I get the screen shown below -
which is followed by two more screen which match a 100% working board.
I know from a friends 100% working game that it should be a completely white screen.
The actual graphics fault is tricky to explain but the best description is little dark squares pattern effect. It is best seen in the title screen - click to open in another window and look in the lower left and right corners of the image. It's like darker squares surrounded by lighter horizontal and vertical lines.
See the image below with the name "sky soldiers"
I checked all ICs relating to video RAM and only found one faulty. I replaced it but no change.
Comparing my board to a 100% working board the only difference I found was around the 8 CXK5814 (6116) RAM chips. On the working board all the I/O pins are chirping away when probed, on my board the higher numbered I/O pins (I/O5,6,7,8 - Pins 13, 14, 15 and 16) on every second RAM chip have some pins chirping, some low and some high. Looking at the board they don't seem to go anywhere but then neither do the Vcc and GND pins on the RAM chips. Surely it's not a triple layer board.
One RAM chip had I/O 5,6,7 and 8 (Pins 13, 14, 15 and 16) all solidly high or low. I changed this chip and you guessed it, no change.
Any ideas other than removing all RAM chips and replacing them?
Does anyone have a schematic?
On switch on I get the screen shown below -
which is followed by two more screen which match a 100% working board.
I know from a friends 100% working game that it should be a completely white screen.
The actual graphics fault is tricky to explain but the best description is little dark squares pattern effect. It is best seen in the title screen - click to open in another window and look in the lower left and right corners of the image. It's like darker squares surrounded by lighter horizontal and vertical lines.
See the image below with the name "sky soldiers"
I checked all ICs relating to video RAM and only found one faulty. I replaced it but no change.
Comparing my board to a 100% working board the only difference I found was around the 8 CXK5814 (6116) RAM chips. On the working board all the I/O pins are chirping away when probed, on my board the higher numbered I/O pins (I/O5,6,7,8 - Pins 13, 14, 15 and 16) on every second RAM chip have some pins chirping, some low and some high. Looking at the board they don't seem to go anywhere but then neither do the Vcc and GND pins on the RAM chips. Surely it's not a triple layer board.
One RAM chip had I/O 5,6,7 and 8 (Pins 13, 14, 15 and 16) all solidly high or low. I changed this chip and you guessed it, no change.
Any ideas other than removing all RAM chips and replacing them?
Does anyone have a schematic?

