Power Mac G4 MDD Will not show video at all when turned on.

Try a PMU reset.

*Resetting Cuda/PMU on Power Mac G5, Power Mac G4, Power Macintosh G3*
http://docs.info.apple.com/article.html?artnum=86760

 Cheers, Tom 😉

Let's see if I can be of some help.

Your Mac model originally came with an ATI Radeon 9000 video card. I am pretty sure that some Mac-compatible ATI video cards are not compatible across different Macs. I don't think the ATI Rage card would've work in this Mac and I don't think your iMAc's ATI 9250 is working in this model,either.
If you can locate an OEM ATI 9000 Mac version, this card works with this Mac.
Also, I replaced my stock OEM ATI 9000 video card in my MDD G4 with an ATI 9600 Radeon PC/Mac edition. This card also works well in this Mac.
Another card that works in this Mac as OEM is the Nvidia Geoforce4 Ti.
If you can find and purchase these cards, you may have a fighting chance to get video up and running on this Mac.

Next, Have you replaced this Mac's PRAM battery with a new fresh one?
If this Mac has been stored without any power connected to it, the PRAM battery is probably completely drained.

Also, an 80GB to 120 GB can be put into this Mac.
They are EIDE/ATA 66 variety
Do you have the original Mac G4 specific system installer disks that came with this Mac?.
If you do, then you need to access the disk utility app from the install CD when it loads to format the new drive as an HFS+ extended (either journaled or non-journaled) before installing any version of OS X (min OS X version for this Mac is OS X 10.2 Jaguar).
YOU NEED THESE G4 MDD SPECIFIC DISKS.
If you DO NOT HAVE THE ORIGINAL SYSTEM INSTALL DISCS, then you need to use an OFFICIAL retail copy of OS X (10.2, 10.3, 10.4 or 10.5). DO NOT USE ANY GRAY COLORED DISCS for other Macs.
Gray colored discs for eMacs usually can boot and install across many Macs but this is usually a crap shoot, at best. Stay away from GRAY discs that weren't explicitly made for the G4 MDD model you have.
Did you install an OS on the HD?
Nothing will happen with the video unless you can boot from valid CD/DVD of the OS.

Another approach is to purchase an external FireWire drive and use either Super Duper or Carbon Copy Cloner to clone a copy of your iMac's OS ( can be OS X Jaguar,Panther, Tiger or Leopard) to the via FireWire to the external drive. Then, plug the external drive into the G4's FireWire ports and see if the Mac will find the OS and boot from the external FW drive.
If it does, then if you have a copy of the cloning app on this drive, you can clone a copy of this system back to the G4 and try booting from the G4's HD (assuming you formatted it as an HFS+ extended format).
Hope this helps you. 🙂

Is your iMac one of the originals?
I am running my G4 MDD Mac with a non-Apple monitor.
Questions and concerns...
Are you using a CRT monitor or LCD panel type monitor?
CRT monitors need a special adapter/connector on back of monitor to accept VGA signals from the Mac. These adapters sometimes have DIP switches that need to be set to set the correct RGB frequencies that the Mac's Video cards send out. Some of these adapters do not have DIP switches and are already configured for Macintoshes
Is the LCD panel using VGA port or DVI/Apple ADC port?
Make sure monitor has dual inputs such as a VGA port and DVI port.
If using VGA, the monitor end needs to connect to a VGA port on the LCD panel or if you have only a DVI port, then a special VGA to DVI adapter needs to be used at the monitor end.
May need to use a cable that is Apple ADC cable at one end and DVI at the other.
Also, if the monitor in question has any onboard controls, onboard menu controls,
These need to be set.
Maybe the brightness is turned down?
Maybe need to setup monitor to accept VGA input signals or DVI input signals if the monitor in question doesn't do this automatically?

Sound as if there is no issues at all with the monitor.
Just covering all of the bases.
Another thing about installing the HD. Make sure that the connectors are making a tight connection and make sure you install the small, plastic isolator blocks to the same pins, on the back of the HD, they were on when you took out the original HD.
I am not sure how the blocks are configured in this Mac, but should be able to find this info here and elsewhere.
The drive needs these blocks to set up the drive with the right pin configuration. Can use either Master or cable select drive pin config modes.

Hi,

I've just had a similar problem with a G4 MDD - no video, CD eject button did not work etc

I did all the resetting connector, RAM, graphics card etc etc reset PRAM, replaced the PRAM battery removed 3rd party RAM etc etc etc.

Having received advice re disconnecting the hard drive and booting from a diagnostic CD, I found my machine had a stuck hard drive caused by 2 and a half years of inactivity.

It would not boot into the OS as a result. You can get the CD drawer to open by holding down the mouse during start up until the drawer opens or manually by opening the outer cover and using a paper clip inserted into a small hole on the front of the drive to release.

Try and get hold of a diagnostic CD, it will confirm which bits of your system are faulty and lead to a remedy.

I have a new HDD on order to sort my own issue out - I will recover the data from the old HDD using tips provided on this forum.

Good luck !!

+Here's the text included in a recent post for info.+

+After resetting all internal connections resetting PRAM, changing battery etc etc as everyone else seems to have done, I tried booting the machine via diagnostic CDs with the HDD connected with results as follows :+

+HDD CONNECTED TO LOGIC BOARD+

+SOFTWARE INSTALL & RESTORE CD – Apple Logo and clock spinner appears but spinner keeps moving around without doing anything further.+

+APPLE HARDWARE TEST CD – booted to loading screen which stuck at the words loading and no further.+

+MAC OS X X CODE TOOLS – nothing showing except grey screen.+

+HOWEVER ….+

+HDD DISCONNECTED TO LOGIC BOARD+

+Although the HDD sounds like its working audibly :+


+I finally got the machine to boot from the APPLE HARDWARE TEST CD having first disconnected the HDD from the logic board. I ran the extended test and everything passed OK.+

+I also booted up using the SOFTWARE INSTALL AND RESTORE CD again without the HDD connected and I got to the normal OS software install menu sequence. I obviously could not reload the OS because the HDD was disconnected.+

+I have reset the HDD IDE connection ie to both the HDD itself and the logic board and the PSU to the HDD.+

+CONSEQUENTLY I THINK THAT THE HDD IS AT FAULT.+

+Anyone got any further opinions/tips please ?+

PS Forgot to mention, video worked fine on Samsung monitor with DVI connection but not RGB.