Dead G5 1.8ghz dual

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Level 3

525 points

Dead G5 1.8ghz dual

G'day,

Woke up this morning to find my G5 was powerless (ie no power). It is always either awake or sleeping, so thought perhaps there had been a minor power outtage overnight... but it would not turn back on.

(In this case, it had been awake, running "Transmission". Heard it "ding" to announce finishing a file at about 1am...)

I tried unplugging everything except for the 17" studio display (only had a firewire cable going to a video camera, ethernet cable coming from Airport Extreme Base Station, and USB hard drive attached), and tried again, but still wouldn't turn on.

What do I try next...? CUDA switch? (Do these machines use one?)

Thanks

cosmic

PowerMac 2004 dual 1.8GHz, Mac OS X (10.5.8), 1.25GHz RAM, 2x 1TB WD Green Drives, Stock Vid Card

Posted on Mar 22, 2012 3:59 PM

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Answer 1

BDAqua

Level 10

239,213 points

Mar 22, 2012 4:39 PM in response to cosmichobo

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

Is there a red LED lit up on the Logic board when AC is connected?

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Answer 2

cosmichobo Author

Level 3

525 points

Mar 22, 2012 7:53 PM in response to BDAqua

G'day mate,

Reset the SMU/PMU...

No good...

There is no visible lights on the logic board when power is connected... I couldn't locate the LED itself, but I do recall seeing one during previous voyages inside the machine.

😟

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Answer 3

BDAqua

Level 10

239,213 points

Mar 22, 2012 8:09 PM in response to cosmichobo

Do you have a multimeter?

2004 PowerMac G5 PSU pinouts

"Stuka" wrote:

A: There is not a single pinout for a G5. It has several connectors that connect to different areas of the board.

Power Supply P1 Connector
Pin# Signal Color ------ Pin# Signal Color
1 +5Vstb Purple --------- 13 GND Black
2 GND Black ------------- 14 Power ON Green
3 FANtach White/Yellow -- 15 GND Black
4 GND Black ------------- 16 Reserved
5 Reserved -------------- 17 GND Black
6 GND Black ------------- 18 RTNaud(GND) Black
7 +12Vaud (12V2) Yellow - 19 GND Black
8 GND Black ------------- 20 +5V sense Red
9 +3.3V sense Orange ---- 21 GND Black
10 GND Black ------------ 22 -12V Blue
11 GND Black ------------ 23 GND Black
12 Reserved ------------- 24 Reserved

Power Supply P2 Connector
Pin# Signal Color ------- Pin# Signal Color
1 +3.3V Orange ----------- 9 +5V Red
2 +3.3V Orange ---------- 10 +5V Red
3 +3.3V Orange ---------- 11 +5V Red
4 +3.3V Orange ---------- 12 +12V3 Yellow
5 Reserve --------------- 13 +12V3 Yellow
6 +12Vfan Yellow -------- 14 +12V1 Yellow
7 +12Vfan(12V2) Yellow -- 15 +12V1 Yellow
8 +25V White ------------ 16 RTNfan(GND) Black

Power Supply P3 Connector
Pin# Signal Color ------- Pin# Signal Color
1 +5V Red ---------------- 5 +5V Red
2 GND Black -------------- 6 GND Black
3 GND Black -------------- 7 GND Black
4 12V2 Yellow ------------ 8 +12V2 Yellow

hth,

dan k

http://www.applefritter.com/node/6561

Not sure how close that is to the 2005 models though.

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Answer 4

cosmichobo Author

Level 3

525 points

Mar 22, 2012 8:49 PM in response to BDAqua

I do have a multi meter, and vague concepts of using one. :}

But just to clarify...

The PSU is in the base of the computer... so somewhere I should be able to find 3 connectors - a 12 pin, 8 pin, and 4 pin... coming up from below... Y/N

And I can then disconnect those connectors, and use the multimeter between the individual pins, to the chassis, to determine if there is voltage or continuity (gnd)... Y/N

(Or do I need to keep the connectors in place, so as to keep the circuits closed, and push the multi meter needle in to find if there is any power?)

:}

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Answer 5

BDAqua

Level 10

239,213 points

Mar 22, 2012 9:03 PM in response to cosmichobo

Y

N, you leave them connect I believe & insert a prob into the connection.

Maybe

Y, I think so.

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Answer 6

japamac

Level 7

24,400 points

Mar 23, 2012 5:23 AM in response to cosmichobo

do I need to keep the connectors in place, so as to keep the circuits closed, and push the multi meter needle in to find if there is any power?

Absolutely.

Have you unplugged the mains once? When replugged, is there a click? Perhaps two clicks?

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Answer 7

cosmichobo Author

Level 3

525 points

Mar 23, 2012 8:55 AM in response to japamac

Can't say I've heard any clicks....

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Answer 8

cosmichobo Author

Level 3

525 points

Mar 23, 2012 2:59 PM in response to cosmichobo

Haven't checked pins yet..

Left PRAM battery out and power plug pulled overnight.... Still nothing and listened carefully this time - no clicks when reconnected.

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Answer 9

japamac

Level 7

24,400 points

Mar 23, 2012 3:24 PM in response to cosmichobo

no clicks when reconnected.

One is common in a normal PSU, two is common in a failed PSU.

None, well, you don't see any fan or LED activity, right?

Testing will only confirm what is likely a dead PSU.

Have you seen this?

http://damntechnology.blogspot.jp/2009/02/rebuilding-powermac-g5-power-supply.ht ml

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Answer 10

cosmichobo Author

Level 3

525 points

Mar 23, 2012 3:57 PM in response to japamac

G'day japamac,

Well, I guess you get what you pay for... and I paid $99 nearly 2 years ago for a machine labelled "NO WARRANTY" at a pawn broker... Just asking for trouble...

Thanks for the link to the PMU rebuild... I can use a soldering iron, but am far from good at it... Think this machine will be getting either parted out, or sold as is for a few bucks to go towards a 2nd hand iMac or Mac Pro...

cheers

cosmic

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Answer 11

japamac

Level 7

24,400 points

Mar 23, 2012 4:34 PM in response to cosmichobo

That's pretty cheap for two years of use.

Likely a used PSU would cost more than what you paid for the entire machine.

The PSU in the G5 has always been a weak link.

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Answer 12

cosmichobo Author

Level 3

525 points

Mar 31, 2012 3:05 PM in response to cosmichobo

As an interesting addendum...

I bought a new dual 1.8GHz G5... just had to insert my optical, hdd, and video card.

Now, running the same settings etc (as its the same hdd), the machine goes to sleep as it is meant to... whereas before it would not sleep unless told to manually.

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Answer 13

BDAqua

Level 10

239,213 points

Mar 31, 2012 3:31 PM in response to cosmichobo

Great to hear, thanks for the report. 🙂

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