G4 Digital Audio and 20" (A1038) Cinema Display -- goes blank on bootup

[flainn]

Hi folks,

I've got a G4 Digital Audio which works great with a CRT monitor.

Yesterday I picked up an A1038 20" Cinema Display (the one with an ADC connector).

When I plug the Cinema Display into my graphics card and power on the G4, it shows me a happy Mac for a few seconds, then the screen goes black. Seems to happen at about the same time it changes from the Happy Mac to the OS X logo.

I've done a fair bit of Google searching for a solution:

- zapped the PRAM, same result
- cleared the PMU by unplugging all the cables and pressing the CUDA button once, waiting ten seconds, and plugging everything back in. Same result.
- Booted into single user mode, mounted the file system, and deleted the file /Library/Preferences/com.apple.windowserver.plist and rebooted -- same result.
- Booted from the OS X 10.1 CD; same result.

Nothing I've tried has worked; the display works great while the Happy Mac is on the screen, then goes blank. The display power light stays on, but the display seems to go completely blank (not just the backlight turning off, but no picture at all -- I shined a bright light on the screen and can't see any picture at all).

Note that I don't think the problem is with the display itself because when I boot into single user mode, it stays on for as long as I want it to.

I also am unable to drive the CRT monitor if the Cinema Display is plugged in; it seems to be one or the other.

Is there something else I can try?

 

[_nec6678]

Do you have another graphics card compatible with the G4 to try the Cinema Display with?

 

[flainn]

Hi, unfortunately I don't -- the only other card I have has a DFP connector and not an ADC connector.

I do have a G5 on its way to me and it does have a card with an ADC connector, but of course that's a PCIe card. But it'll hopefully give me more evidence that it's not the display itself that's the problem.

I suppose I could try to pick up another cheap graphics card for the G4 that has an ADC connector.

 

[phunguss]

Could it be trying to go to a resolution that is not supported? What resolution is your CRT? Try connecting your CRT, fully boot, set the resolution as low as you can go and shutdown, remove CRT, add ADC monitor and boot back up.

I don't have a 20" to test things.. but I do have 17", 22", and 23" ADCs. I have replaced the CCFL backlights in two of the 17" because they had issues with the CCFL drivers (one the power button blinks 3 times and then turns off, the other never showed anything on screen).

 

[flainn]

I looked at the available resolutions (using my CRT monitor) and none of them seem to be supported by this display, which may be the issue. The ones OS X 10.1 wants to let me use with the CRT are the standard ones (800x600, 1024x768, 1280x1024, etc). The resolutions this Cinema Display supports, apparently, are 1024 by 640, 1280 by 800, and 1680 by 1050 (optimum) -- none of which is offered by the control panel.

Just to try, I set the resolution to 800x600, shut the system down, and reconnected the flat panel and got the same result as before.

 

[phunguss]

So when you fully boot into safe mode, what is the resolution? Do you have any other boot drives or optical media to boot from? Sounds like a software conflict.

 

[flainn]

Same result when trying to boot into safe mode.

There's no software installed; just a clean install of OS 9.2.1 and OS X 10.1.2.

 

[phunguss]

Can you boot into 9.2.1?

 

[flainn]

Yes, able to boot into 9.2.1 with the CRT monitor; can't get anything to display with the Cinema Display.

 

[phunguss]

not just the backlight turning off, but no picture at all -- I shined a bright light on the screen and can't see any picture at all

I could not see a picture on one of my 17" displays with a bad inverter board. The power light stayed on, but the flashlight test did not work for me either. I replaced the backlight with an LED strip and it works great. There are two boards inside the display, one is a logic/graphics board and the other is the inverter. Check my thread here... I see I never updated my 2nd version... I will try to do that now.

 

[flainn]

I hope I don't need to go that deeply into this project to make this thing work, but it does sound fun.

I'm going to try installing 10.4.11 and see if that makes any difference. I had a hunch that since this monitor wasn't released until early 2003, maybe running an OS released after that (rather than 10.1) will make things play better. Who knows.

 

[joevt]

Why don't you have 10.4 or 10.5 installed?

Use a screen sharing app so you can see what the OS is seeing when the display goes blank? I think 10.5 has built-in screen sharing. For 10.4, you can install a VNC Server.

Install SwitchRes for Mac OS 9 or SwitchResX for Mac OS X to give you more display resolution choices?

 

[flainn]

Haven't had any success attempting to get 10.4 or 10.5 installed so far (no media I've found actually boots on this machine).

I'll try SwitchRes/X, thanks!

 

[joevt]

Haven't had any success attempting to get 10.4 or 10.5 installed so far (no media I've found actually boots on this machine).

I would try putting the installer into a partition of the hard drive if you can't boot CD or DVD or FireWire.