View Full Version : PowerMac G5 With ADC Connector - Monitor Displays Only After Reseating Power Plug

05-18-2009, 07:10 PM
I worked on a PowerMac G5 last week with a Cinema Monitor that used an ADC connector. The ADC cable carries the video signal as well as USB and power to the monitor. The monitor does not require a dedicated power cord to operate.

Anyway, the only way that the display worked was if I unplugged the power cord from the computer and replugged it in. When you would shut down the Mac properly, it would turn off, then when you went to turn it back on, it would get power to the display but no display.

I re-seated the video card, upgraded the OS, reseated the memory and reseated the CMOS battery and still no resolution. The funny thing is if you plugged a regular DVI monitor into the DVI port (without the ADC monitor hooked up) it would work just fine.

I think the problem was with either the video card or the system board - just never heard of this issue before.

The customer came in with a totally different issue and said that this was always the way the computer worked so I left it alone. I'm just curious what it could have been. Seems kind-of ridiculous to have to unplug your computer and plug it back in every time you want to turn it on.

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anonymous Mac Tech
05-18-2009, 09:27 PM
Hey! another Mac person. I was starting to think I was a lone cowboy on this ranch.

Yeah those ADC connectors and those older cinema displays are kind of goofy. Was the Cinema display an old standard 17-inch or a big 23-inch? I know it takes a higher powered card to run those larger cinema displays sometimes. Other than that just make sure the connection is good and seated into the card? I suppose it could be the card, except its strange it worked great through DVI?

05-18-2009, 11:20 PM
It was a 23 inch Cinema Display. It probably was the video card but I guess we'll never know unless the customer wants it fixed. I was pricing those Radeon cards out and they are not cheap - probably around $500 to replace on the cheaper side - unless I was looking in the wrong place.