[SOLVED] 'init 3' kills video signal

Todays updates features a bunch of KDE packages (more than 280 on my system), so I decided to do it without running KDE. The usual way I get out of the X environment is the command 'init 3' in a root terminal. Today, after giving this command the screen went black immediately and seconds later showed the message "No DVI signal" (showing the yellow LED) as if it was not connected or no system running on the computer. The computer was still running as shown by the control LEDs.
Shutting off by power button and rebooting the same happened in 3 following attempts.
- Graphic system is nvidia with the current proprietary driver.
- 'init 3' from a root konsole usually succeeded in shutting down the X server and presenting me with a login prompt
After rebooting into RL3 I did all the updates, rebooted normal way into KDE, no problems. So I would not think it to be a hardware issue.
Shutting off by power button and rebooting the same happened in 3 following attempts.
- Graphic system is nvidia with the current proprietary driver.
- 'init 3' from a root konsole usually succeeded in shutting down the X server and presenting me with a login prompt
After rebooting into RL3 I did all the updates, rebooted normal way into KDE, no problems. So I would not think it to be a hardware issue.