4 Replies Latest reply: Nov 21, 2009 7:14 AM by tdefrange
marcelle33 Level 1 (0 points)
I recently switched from an old G4 tower to a less-old G5 tower with dual 2GHz processor and a GeForce 6600LE graphics card. The monitor I was using with the G4 is a Viewsonic VX2025, and they worked flawlessly together. Not so much for the G5. The monitor, which is connected via one of the two DVI ports on the G5, works when the computer is started cold. However, after a period of inactivity or sleep, the monitor goes black and will not receive a signal. The power to the monitor remains on, but the light on the monitor is yellow. If I tap the keyboard or click the mouse I can hear the tower powering up, and my mouse will flash its light, but the monitor will remain black. At this point I will have to power down via the power button. Occasionally, however, the G5 will not power down and I'll have to disconnect the power source. At this point turning the computer back on will result in the same black monitor screen unless I wait at least 20 minutes to turn it back on. In which case, everything will work fine as long as it doesn't go to sleep.

I've tried re-seating the power cord for the monitor, and checking the connections.

Now, I've switched to an old VGA monitor that I dug up from the garage with a DVI adaptor. This system works fine and I've had no problems. However, the monitor quality isn't very good and I need to figure out a way to get the G5 working with my Viewsonic. Any suggestions?

Dual 2 GHz PowerPC G5, Mac OS X (10.5.8), GeForce 6600LE Viewsonic VX2025
  • kmac1036 Level 4 (2,360 points)
    reset your PRAM & PMU.

    PMU / CUDA: http://support.apple.com/kb/HT1939

    PRAM: hold command option P R at startup until you hear the chime a 2nd time.
  • marcelle33 Level 1 (0 points)
    Thanks, but I did both of those things today and they had no effect. I started up the computer and stepped away from it for a while, and when I returned the monitor was again not picking up a signal from the G5. The screen was black and I had to manually shut down.

    It's strange. The G5 works with other monitors, and the Viewsonic works with other computers, they just aren't working with each other.
  • tdefrange Level 1 (0 points)
    I have a Power MacG5 behaving exactly the same way with a large Westinghouse (LCM.22W) LCD Monitor. The problems began when I decided to enable the sleep function to save electricity. For years it worked fine and the sleep problems into an unwakable black screen started on and off with me doing the same to remedy it: restarting or unplugging and replugging the DVI 400 cable (Monster Digital Video)from the CPU DVI port. Now nothing works as a remedy. I have no alternate monitor to use to access the CPU. Now when I reseat the DVI cable the monitor says check connections indicating it isn't hooked up to a DVI output video source even though it is.

    I'm starting to wonder if the problem is the G5 video card in the CPU and not the cable or the monitor since I'm not the only one who has experienced the problem with a large monitor when the computer goes to sleep and the monitor shuts down.
  • tdefrange Level 1 (0 points)
    The PRAM PMU reset maneuver looked like it didn't work at first: black screen but there was no prompt saying to check to see if output device is connected. So, just make sure the PRAM PMU reset had truly failed, I unplugged and replugged the DVI cable in the back of the CPU. Voila, the screen lit up. The support document said that all peripheral device cables should not be connected when resetting PRAM PMU. But in this instance, reseating the DVI cable after the maneuver worked to get the DVI signal to the display. Thanks so much, kmac1036.