Verify cables connected properly to the back of the scanner
If the scanner is a parallel port scanner it is likely it has two available connections on the back of the scanner. Verify that the cable coming from the computer is connecting to the IN, Computer IN, computer, or similar connection.
Ensure that the scanner is getting power
If your scanner is not getting power it is recommended that you check the connections ensuring that they are connected properly to the back of the computer and from the scanner to the wall. If you have the scanner connected to a power strip or surge protector it is temporarily recommended that you connect the scanner directly to the wall.
If the computer scanner is getting power, you should notice the inside light come on when the power is first received by the scanner.
After checking the connections you still get no power to the scanner, it is recommended you contact the manufacturer of the scanner.
Parallel port scanner troubleshooting
If you have another device connected in between the scanner and the computer, turn off the computer and temporally disconnect the devices connected to or from the scanner. If, after disconnecting these devices, the scanner works, it is likely that another device may have issues or may be unable to work with other parallel devices.
PC Windows users verify no TSRs are running in the background
Press CTRL + ALT + DEL and end task all currently running software except explorer and Systray and scan again. If this resolves your issue it's a possibility that an application in the background such as a virus utility is preventing your scanner from scanning.
Verify the LPT port mode
PC users ensure that the LPT port mode within the computer BIOS is set to either EPP or bi-directional mode or try alternating between these two modes.
Update the drivers
Verify that the latest drivers are installed for the operating system being used on your computer. A listing of computer scanner manufacturers and links to the drivers pages can be found on our scanner drivers page.