Q: iMac g5, no video output

I just replaced the logic board and power supply on my G5 imac, both of which were bad. Now, when I power on, all three LEDs on the logic board come on, t there's no video output. The video had been working fine before the logic board and power supply failed.

THe tech note says to try resetting the PRAM. We have a wireless (usb) keyboard, and holding down option-apple-p-r doesn't seem to do anything. Is there another way to reset the pram?

Any other suggestions would be welcomed. Replacing

iMac, Mac OS X (10.5.8)

Posted on Mar 10, 2015 1:22 AM

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Q: iMac g5, no video output

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by Mike Sombrio,

Mike Sombrio Mar 10, 2015 3:58 AM in response to jake_blues
Level 6 (17,194 points)

Apple Watch

Mar 10, 2015 3:58 AM in response to jake_blues

USB doesn't load early enough in the startup process to work. You need a wired keyboard.
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by jake_blues,

jake_blues Mar 10, 2015 2:29 PM in response to Mike Sombrio
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Mar 10, 2015 2:29 PM in response to Mike Sombrio

THanks Moke.

OK, I bought a wired keyboard and tried to reset the pram. I think it worked -- it rebooted the computer and the chime came on again. But there's still no video output. Not sure if that means I should replace the screen or the video inverter or both or if it could be something else altogether.

Any ideas?
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by Mike Sombrio,

Mike Sombrio Mar 10, 2015 2:33 PM in response to jake_blues
Level 6 (17,194 points)

Apple Watch

Mar 10, 2015 2:33 PM in response to jake_blues

Sorry no. Is this computer really worth all the resources you're putting into it?
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by jake_blues,

jake_blues Mar 10, 2015 2:45 PM in response to Mike Sombrio
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Mar 10, 2015 2:45 PM in response to Mike Sombrio

Eh, probably not. But the data on the hard disk has some value, and so if I can get it working for less than the cost of having that data pulled, I guess it's at least a break even proposition.
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by Chris CA,

Chris CA Mar 10, 2015 2:47 PM in response to jake_blues
Level 9 (79,426 points)

iPhone

Mar 10, 2015 2:47 PM in response to jake_blues

jake_blues wrote:

Eh, probably not. But the data on the hard disk has some value, and so if I can get it working for less than the cost of having that data pulled, I guess it's at least a break even proposition.

You can buy an external hard drive case for ~$10 and put the drive in it and plug it into USB.
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by jake_blues,

jake_blues Mar 11, 2015 5:21 AM in response to Chris CA
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Mar 11, 2015 5:21 AM in response to Chris CA

Ah, brilliant! Had no idea those existed. Thanks very much; that's the route I will go, then.
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by rccharles,

rccharles Mar 12, 2015 3:11 PM in response to jake_blues
Level 6 (8,439 points)

Classic Mac OS

Mar 12, 2015 3:11 PM in response to jake_blues

Try safe boot. If the video chip or card is bad, safe boot doesn't use the chip, instead, everything is down in software.

Try a safe boot.
     Shutdown your machine. Hold down the shift key. Poweron. Wait awhile; wait awhile while you harddrive
     is being checked.
     h
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Q: iMac g5, no video output

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