OpenBoot 3.x Command Reference Manual

Blank Screen --No Output

Problem: Your system screen is blank and does not show any output.

Here are possible causes for this problem:

Refer to your system documentation.

If the keyboard is not plugged in, the output goes to TTYA instead. To fix this problem, power down the system, plug in the keyboard, and power on again.

Check the power cable on the monitor. Make sure the monitor cable is plugged into the system frame buffer; then turn the monitor on.

This means the NVRAM parameter output-device is set to ttya or ttyb instead of being set to screen. Connect a terminal to TTYA and reset the system. After getting to the ok prompt on the terminal, type: screen output to send output to the frame buffer. Use setenv to change the default display device, if needed.

If your system has several plugged-in frame buffers, or it has a built-in frame buffer and one or more plugged-in frame buffers, then it is possible that the wrong frame buffer is being used as the console device. See "Setting the Console to a Specific Monitor".