HT Games
Game Cartridge
Insert the Action Replay DS into the slot of the Nintendo DS used for GBA games. The Action Replay cartridge has its own slot in which to insert a GBA game. To use the Action Replay, you must have a GBA game inserted in this slot. This also applies if you want to use the Action Replay with DS games. The Action Replay cartridge must be inserted for it to register with the system.
Action Replay Switch
The Action Replay cartridge is equipped with a switch to enable or disable cheat codes while playing a game. It does not reset the game or system. Turning the Action Replay cartridge off with this switch can cause it fail to register with the system. There are no markings on the cartridge to indicate which direction the switch should be pressed, but pushing the switch to the right turns the cartridge on.
Loose Connection
The Action Replay cartridge must be inserted fully to ensure a proper connection with the Nintendo DS system. The GBA game in the Action Replay cartridge slot must also be fully inserted to connect properly. Always turn off the Nintendo DS before checking the connections, inserting cartridges or removing cartridges. The best way to try to ensure the connections are fully made is to remove and reinsert both cartridges.
Hardware Defects
The Action Replay cartridge might not register with the system because one of the hardware components has become faulty. The GBA slot on the Nintendo DS might no longer be able to read games. You can test this by inserting a GBA game directly into the slot on the system to see if it works.
Alternatively, the GBA game in the Action Replay may be faulty. You can test this by trying to insert a different GBA game into the slot. The Action Replay cartridge can also develop faults over time. If nothing else fixes the issue, it is most likely due to a fault with the Action Replay. Inserting and removing cartridges while the Nintendo DS is turned on is a significant source for GBA and Action Replay cartridges becoming faulty.