Variant: Nichibutsu
Problem: No player shot sound
Fix: Replaced the 555 timer at 7S
Problem: No player shot sound
Fix: Replaced the 555 timer at 7S
Moon Cresta
- Thread starter Adrian Purser
- Start date
Variant: Nichibutsu MC-1FJ
Symptom: Bad Colours
Diagnosis: Ouput Pins 6 and 8 on the 7420 @ 3P were stuck at about 1.5V. Input pin 4 was shorted to +5V causing the signal CC2 to be pulled up.
Fix: Replaced the 7420 @ 3P
Symptom: Bad Colours
Diagnosis: Ouput Pins 6 and 8 on the 7420 @ 3P were stuck at about 1.5V. Input pin 4 was shorted to +5V causing the signal CC2 to be pulled up.
Fix: Replaced the 7420 @ 3P
Variant: Nichibutsu MC-1FJ
Symptom: Bad Graphics. Missing graphics on the right side of the screen. Graphics wrapped around to the left side.
Fix: Replaced the 2101 RAM @ 5F.
Symptom: Bad Graphics. Missing graphics on the right side of the screen. Graphics wrapped around to the left side.
Fix: Replaced the 2101 RAM @ 5F.
Variant: Nichibutsu MC-1FJ
Symptom: No Sync
Diagnosis: The outputs of the 74LS161 counter @ 6A were stuck low. VSYNC is on pin 11 of this device.
Fix: Replaced the 74LS161 @ 6A
Notes: If either the HSYNC or VSYNC signals are stuck low then the CSYNC output will be stuck low causing complete loss of sync.
Symptom: No Sync
Diagnosis: The outputs of the 74LS161 counter @ 6A were stuck low. VSYNC is on pin 11 of this device.
Fix: Replaced the 74LS161 @ 6A
Notes: If either the HSYNC or VSYNC signals are stuck low then the CSYNC output will be stuck low causing complete loss of sync.