The clunky cartridge button is the naming of a defect found on an early build of the US NES. Nintendo later created build 2 with a vertical load pin tongue for the same reason why no other game system adopted this cartridge loading system. With the clunky cartridge button, pin-conduction was poor; therefore NES model-1 had a chance of graphical defects.
Graphical defects caused by this
- Scrambled screen
- Bogus detour to other patterns (e.g. parallel vertical lines instead of a horizontal contiguous line).