07-26-2011, 02:07 AM

Hey Guys,

So recently I acquired a G5 PowerMac 1.6 processor for a great price. I had it working wonderfully last night....we sorta.

At first when I plugged the PowerMac in I didn't get a chime or video. Luckily I had a compatible video card on hand, and dropped it in. Bingo, it worked like a charm. About an hour later, I threw in some memory to knock it up to 2 GB, again all was good. Then the fun started.

I went to replace the hard drive and BAM. No more chime or video. Ok....so I added the original back and the same thing happened again. I reseated all my memory as well as the video card and everything was fine. Then after a restart I had the no video or chime again. I put all of the original hardware back in and the same thing happened.

I reset the PMU by pressing the button on the board, tested the PMU battery (which is fine), and verified the power supply was outputting the correct power with my multimeter.

I have now removed the PMU battery and hit the PMU reset button and am leaving it off for 10 minutes to see if it helps. I doubt it will. This sounds to me like either a processor or a logic board. I welcome any tips/tricks/opinions. I got this thing for 40 bucks and I'm hoping to bring it back from the dead. I'm hoping its not a board, but since I had it working so well last night I'd be kinda surprised that it would go in a matter of minutes. Then again, I know nothing of it's past history.

This sounds to me like either a processor or a logic board. I welcome any tips/tricks/opinions. Thanks =)

07-26-2011, 02:30 AM

It sounds like the logic board to me. As you seem to have already eliminated almost all other possibilities. One thing besides that is that it may be the video card you installed is dodgy, and not working 100% of the time. Are you sure it's in 100% working order?

07-26-2011, 02:39 AM

Originally Posted by MacDude121

It sounds like the logic board to me. As you seem to have already eliminated almost all other possibilities. One thing besides that is that it may be the video card you installed is dodgy, and not working 100% of the time. Are you sure it's in 100% working order?

Yep, works flawlessly in my G4 as well (which my wife uses daily), its a really nice 256 Radeon. When I first dropped it in this PowerMac it worked like a charm for an hour or so until I powered it down.

Now when I hit the power I get no chime, but a soild power light. Fans then start out nice and quiet and progressively get louder and louder. It sounds like someone it slowly pressing down on an accelerator pedal.

07-26-2011, 09:27 AM

Been a while since I have worked on one of these but........

No chime, well that could be a power supply issue or a motherboard popped!

I take it these have the diagnostic led's on the motherboard 1, 2, 3, 4.......if so when you you do the reset is led 1 coming on.......is led 2 flickering on.......

This will give you an idea from the start, if 1 comes on it means there is power but not necessarily the right power to power up.....if led 2 flickers then that means power is getting to the motherboard....

I have known people to test the power supply and believe it was Ok but were wrong......

Could be something as simple as a cold solder and all the tinkering inside is moving it about or made it worse......

Otherwise have you tried resetting the Pram.......

07-26-2011, 10:48 AM

Yep. I've definatley done the pram. I do have a power supply Coming in the mail, I got a really good deal on one. I dont get any LEDs flashing unfortunately. I actually don't believe the original g5 powermac had those.

07-26-2011, 11:04 AM

As for LED's, if it is a late 2005 it will have 5-7 of them near the Dimm sockets.....although I am not sure what each one represents: About the Power Mac G5 (Late 2005) diagnostic LEDs

Obviously you also have the power light LED on the front, is this on.....or is it is flashing....if it is flashing then you may have RAM issues......

Personally I think it is the power supply and you have gone the route I would have gone.....but I am always cautious before spending money.....lol

07-26-2011, 02:03 PM

I'm sure you've thought of this but just in case, the power supply on the G5's has a sensor built into it where if the clear plastic insert (the large one behind the opening side of the case) it will not function. I played around with mine and got the same fan behavior (sounds like i floored it in my honda) make sure the lower right hand tap (it has a small opaque covering on it) is seating correctly, otherwise the computer will know the insert is gone, and thus, cannot cool itself the way it wants to. it just gets angry until the piece is back in and rebooted. The G5's were built with 4 cooling chambers and this piece keeps them separated. just a thought, hope it helps.

07-26-2011, 06:25 PM

A 1.6GHz processor is the earliest model G5 and not a late 2005 model and think you are on the right track with the power supply as the diagnostic LEDs are not operating.

Also worth checking the clear plastic wind deflector is correctly fitted as you have had the machine open.

07-26-2011, 11:06 PM

Originally Posted by Markymark123

As for LED's, if it is a late 2005 it will have 5-7 of them near the Dimm sockets.....although I am not sure what each one represents: About the Power Mac G5 (Late 2005) diagnostic LEDs

Obviously you also have the power light LED on the front, is this on.....or is it is flashing....if it is flashing then you may have RAM issues......

Personally I think it is the power supply and you have gone the route I would have gone.....but I am always cautious before spending money.....lol

Thanks for all the replies guys. I managed to order a PS for 10 bucks =) so I'm gonna try that out. I'm almost positive the plastic clear piece is in correctly but i'll double check.

I didnt see any LEDs other then the power light, does the 2003 1.6 have them on the board?

07-26-2011, 11:11 PM

Yep plastic thing seated fine. Hopefully its the power supply. I'm keeping my eyes out for a board on ebay as well.

08-01-2011, 01:26 AM

UPDATE!

Replaced the Power Supply=No luck. Replaced the Processor.....BINGO.

Boots like a champ. However fans race because thermal calibration is necessary. Time to visit the Apple Store!

08-01-2011, 07:59 AM

Originally Posted by XMARLTONX

UPDATE!

Replaced the Power Supply=No luck. Replaced the Processor.....BINGO.

Boots like a champ. However fans race because thermal calibration is necessary. Time to visit the Apple Store!

Congrats on making some positive progress...but it sounds like this $40 Powermac G5 may cost more in the end than you think.

Keep in mind that a fully operational Powermac G5 with a 1.6ghz cpu is only worth about $150 bucks. I know that there's the "challenge" of getting this thing working...and the satisfaction of figuring out the problem(s)...just a reminder about the financials.

Continued good luck,

- Nick

08-01-2011, 01:30 PM

I hear ya. So far I'm $60 into it, so if I keep it here, I'm happy.

08-01-2011, 01:59 PM

Originally Posted by XMARLTONX

I hear ya. So far I'm $60 into it, so if I keep it here, I'm happy.

You're right...if you end up with only $60 for that computer it's a pretty good deal!

Since you mentioned replacing the power supply & processor (both usually VERY expensive parts for a Powermac G5)...it sounded like things we're getting expensive.

A visit to the Apple Store may or may not be productive...some of the employees may not even know what a Powermac G5 is. They'll probably think it's some sort of "mutant" Mac Pro with only one CD/DVD drive door! If you do need their help...they may also charge you some $$$ (adding to the cost of the project).

Again...good luck,

- Nick