blackscreen upon startup/keyboard responsive g5

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blackscreen upon startup/keyboard responsive g5

Have an old dual 5 tower that my wife uses (was mine). Screen is black at startup, the keyboard/mouse is unresponsive and the fans go into overdrive. Any ideas or are we talking landfill here....

iMac

Posted on Feb 3, 2014 2:05 PM

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Answer 1

BDAqua

Level 10

239,177 points

Feb 3, 2014 3:21 PM in response to wsflynn

Hello, tough to tell, but...

Disconnect all Power & all peripherals, pull the PRAM Battery out, let it sit at least an hour then replace the PRAM Battey & AC power cord, plug Monitor, mouse, & Keyboard back in.

Hold alt key at power up... any signs of life?

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Answer 2

wsflynn Author

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Feb 4, 2014 10:53 AM in response to BDAqua

No go. Just noticed, no chime either!

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Answer 3

BDAqua

Level 10

239,177 points

Feb 4, 2014 5:59 PM in response to wsflynn

Might be time to replace the PRAM Battery, 4 years is close to their lifespan, far less if ever without AC power, & can cause strange startup problems...

See which one your G5 has...

http://eshop.macsales.com/item/Newer%20Technology/CR2032/

http://eshop.macsales.com/item/Newer%20Technology/BAA36VPRAM/

If you remove the side cover, is there at least 1 LED lit on the Logic Board?

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Answer 4

wsflynn Author

Level 1

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Feb 14, 2014 12:27 PM in response to BDAqua

Installed new battery. Get the chime now. The monitor light goes on, but the the screen stays black. Didn't unplug it when I put the battery in, but turned all the power off. Fans still go nuts, just takes a little more time.

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Answer 5

BDAqua

Level 10

239,177 points

Feb 14, 2014 2:27 PM in response to wsflynn

Have you done a PRAM reset, CMD+Option+p+r...

http://support.apple.com/kb/ht1379

In fact, do 3 in a row, takes a bit of time.

How to reset the SMU/PMU on a Power Mac G5 (Late 2004) or Power Mac G5 (Late 2005) ...

http://support.apple.com/kb/HT1436

Earlier G3, G4, G5 models...

http://support.apple.com/kb/HT1939

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Answer 6

wsflynn Author

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Feb 15, 2014 11:01 AM in response to BDAqua

Don't get second chime. Reset the SMU too. Could the battery be in backwards?

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Answer 7

BDAqua

Level 10

239,177 points

Feb 15, 2014 12:01 PM in response to wsflynn

Could be, but which battery is it?

The 3.6v one should have a tiny + sign on the logic board near it, as I recall, the CR2032 went in with the button inwards... but not 100% sure.

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Answer 8

wsflynn Author

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Feb 15, 2014 12:34 PM in response to BDAqua

Positive pointing to the left from the base up? Would it still chime if it were in backwards?

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Answer 9

BDAqua

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Feb 15, 2014 1:05 PM in response to wsflynn

I had an MDD Mac chime with the battery in backwards, but not start... of course battery went dead in short order.

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Answer 10

wsflynn Author

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Feb 15, 2014 1:34 PM in response to BDAqua

It's the Pram battery. Can't find a the polarity sign on the CPU. Any harm in flipping it to see what happens?

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Answer 11

wsflynn Author

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Feb 15, 2014 1:57 PM in response to wsflynn

This is how the battery is inserted,

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Answer 12

BDAqua

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Feb 15, 2014 2:46 PM in response to wsflynn

I'm not sure if it could do some possible harm or not to switch ot, it didn't kill mine immediately anyway.

The very tiny + sign on the logic board was not easy to see. Some moldels had the + sign molded into the plastic holder as I recall.

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Answer 13

wsflynn Author

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Feb 16, 2014 9:37 AM in response to BDAqua

Turns out the battery was in backwards the whole time. Flipped it and get the startup chime, but still black monitor and fans go turbo. Tried resetting the pram several times before I flipped it so restarted the computer each time. Never got the second chime and don't get it now. Did I fry the battery?

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Answer 14

BDAqua

Level 10

239,177 points

Feb 16, 2014 11:02 AM in response to wsflynn

Tough to say, if you have a multimeter you can check the voltake with a 1K resistor in series, but I suspect if you get one chime it might have some life left.

Fans should go turbo for safety if it has any problem, did you do the PRAM Resets again?

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Answer 15

wsflynn Author

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Feb 16, 2014 11:53 AM in response to BDAqua

Don't get the second chime with pram reset so no go. Perfectly good monitor stays black, not much else to do. Got startup chime even when the battery was in backwards.

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