Colordreams Attempt #1
Valid for REV A, REV B, and AGCI boards
How it works:
This defeater seems to be quite primative. It is just essentially a three transistor
amplifier connected to the lockout pin through a capacitor. I assume at startup, and possibly
during the NMI routine they pulse D3 on the mapper. This would generate a -.6V signal and
a positive voltage signal on the line to disrupt it. I have never actually tested one of
these carts on an unmodded NES, so I don't know how well the circuit works.
What's amusing about these carts, is they scratched all the part numbers off. I don't know why
they did it, since the circuit is so simple- not like it was difficult to figure out. Later on
though, they appeared to have stopped the practice. AGCI however went so far as to have custom
part numbers stamped on the transistors and chip!
Operation is really simple. Toggling D3 causes voltage spikes to appear on the lockout chip
pin. Q2 drives Q1 and Q3 which are set up as a simple inverting buffer stage. These then
drive the capacitor, which finally runs to the lockout pin.
I have NO idea what D2 is supposed to be doing. The 10K resistor is so high in value that
it probably does nothing.