CO24926, Rev A, Rev B, Rev B with resistor

Schematic

This is the standard 7800 cart that can hold up to 32K of data. This data appears in the address range from $8000-$FFFF. I have seen three revs of the PCB. Rev A (above left) lacks a deglitching capacitor on the PCB but you can see it was added on and soldered directly to the pin on the ROM. Rev B (above center) has a spot on the PCB for the capacitor. Some versions of the PCB (above right) also have a resistor connected between the pad on the PCB and pin 28 of the ROM, not sure of it's purpose. There is also a Rev C (not pictured) doesn't have any discernable differenced from Rev B.