The images you take with your PDC 640 camera are stored on a removable 3.3V SSFDC or SmartMedia 2 MB memory card (also available in 4 MB and 8 MB). Note: You must insert the memory card before you can turn on the camera.
If camera beeps is enabled, the camera beeps if the card is not installed and displays the [ ] message on the Status panel.
To insert the memory card:
1. Make sure the lens cover is closed (the power is off).
2. Open the memory compartment on the side of the camera.
3. Insert the memory card into the slot (gold side of the card facing the front of the camera).
Make sure the card is pushed firmly into the slot. Note: The camera prompts you to format the memory card if it is not formatted. The camera displays the format menu on the LCD viewfinder. Press the button next to Format.
4. Close the memory compartment cover.
If you can, try using a different memory card. Else, your memory card contact terminals inside the camera may have become worn, causing the camera to not recognize the card once it is inserted.
I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514