Ask Max: My monitor no longer works with a G3.
Have a G3 Minitower connected to a monitor.Cannot get the monitor to light up, does not get a signal, goes into a power saving mode.Tried resetting the Pram, installed new battery.Have other Macs, but this has become a hobby to find the answer.
A display constantly going to sleep mode would indicate to me that the monitor is not getting any signal. The first step is to check the condition of the monitor and its cable. If you can, try the monitor with another known good computer. If it fails with another computer then it is a problem with the display and it is often best to just replace the display altogether. If the display works, then the next place to look is with the video connections. Sometimes it's necessary to have an adapter between the computer and monitor cable. On old G3 computers, VGA displays need a special adapter to connect to the Mac. Sometimes they had dipswitches that could get knocked out of position. Other times the adapters had screw connectors that, if not tightened down, would keep the adapter from staying connected. Sometimes these adapters just go dead. I have even seen the adapters included with Mac minis die after only a few uses, so never assume that an adapter that has worked will always continue to work. If you are not using an adapter or you know it to be working, then the only other suspect would be the video card. Some models have removable video cards. If you can remove the video card, it's best to pull it out and then reseat the card. If it was loose, that will put it right again and if the connectors were corroded then pulling it out and sliding it back in will clean the contact points. If the video port is part of your computer's logic board, you may have to stop your work there. Many video problems with those computers require the replacement of the logic board.