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View Full Version : Help Needed: Rescuing A G5



iMic
12th February 2014, 07:54 PM
I picked up a Dual 2.7GHz Power Mac G5 from hard rubbish today. It doesn't look half bad, specs are nice, but it has one teeny tiny little problem.

http://s10.postimg.org/5c2plk7d5/photo.jpg

No, it's not a Liquid Cooled model. It's water damaged. After giving it a clean, the Logic Board looks to be repairable and it's already cleaned up rather nicely. The PSU is absolutely screwed though. The corrosion inside is so bad, some of the traces are missing from the board.

I don't really feel like killing another Power Mac G5. Enough of them are already being destroyed and their cases repurposed to fit ATX boards into them. So I need to find another G5 Power Supply from somewhere.


I know the most common answer is eBay but I'm working to a ridiculously strict budget here. I can spare a few dollars here and there, but $100 for a replacement unit isn't about to happen.

Think anyone can help a fellow Vintage Mac repairer and enthusiast out or point me in the right direction?


Old PSU is an ACBel 600W, Apple P/N 614-0306. I'm not sure if a higher wattage PSU will work in this machine or not, but I know the 1kW PSUs have different plugs so ideally it would be worth avoiding those.



I also have a Single 1.8GHz G5 that's missing its power supply. That one's a 430W PSU. If I could get a 430W PSU, I'd fix that machine instead since it's a little more complete.


Cheers,
Michael


PS. Gah. Just realised the front fans are missing too. Wonderful.

Edge
13th February 2014, 08:19 AM
IMO, your only play here is to repurpose an ATX power supply into the casing of the G5 power supply (whether you use the corroded case or an alternative case.)

It's time and electrical knowledge versus the cost of a replacement G5 power supply (which aren't cheap, as you've established.)

Byrd
13th February 2014, 10:39 AM
It's stuffed - no chance in hell that the motherboard will have survived possibly months of water logging. I just sold my spare G5 towers for $61 each on eBay (Dual CPU 2.3 and Dual Core 2.3 models), and they were specced out and immaculate - I reckon you could find one locally for < $50 quite easily.

iMic
13th February 2014, 12:50 PM
I haven't seen a G5 available locally for less than several hundred dollars, and I've been looking for a long time. It actually reached the point where I considered having one couriered in from interstate.


The Logic Board looks good - no corrosion on it anywhere. The corrosion you see on the board in the above photo is the powdered corrosion that fell onto the board from the power supply when I tilted the machine on its side. With a brush it dusted right off. I'm fairly confident the board is in perfectly good shape.

Having removed the dud PSU, it's safe to say there's now no corrosion or rust in the machine anywhere, so it's now at a safe point to begin rebuilding from. I'll have a bit of a look around and see if I can scrounge up a power supply from somewhere before I consider other options. I had thought about going to ATX, but the best PSU I have here is an Antec TruePower 550W, which doesn't meet the peak requirements of the Dual G5 (600W min).


I believe I know where the water came from as well. The case specifies the system as a "Dual 2.7GHz", which was a Liquid Cooled machine, but this machine has air-cooled CPUs. I'd say the LCS leaked causing the damage we see here, and the processors and possibly the logic board were swapped in to this chassis later on. Will be difficult to say what processors are in there without powering it up.



Also, sidenote, somewhat interesting... I also picked up a Quad 2.5GHz G5 with the Cooligy / Delphi Liquid Cooling System. This one I'm determined to repair. It's a complete system with no major leaks, possibly some crystallisation on the CPU card however. Since the unit is engineered with automotive grade components, I'd like to have a crack at it. If it's anything like a Mitsubishi cooling system, it should be a fun project.

macman142
13th February 2014, 05:30 PM
That G5 looks pretty stuffed. Even if it's repairable it'll be unlikey to still be a 2.7GHz model if the LB and processors have been replaced.

I'd concentrate on the 2.5 instead.

The cooling units are interesting. The main problems I see is that coolant attacks plastic and rubber over time (as it does in cars). The plastic parts of the unit will be degrading with time. You can probably quite easily replace hoses and hose clamps but the actual pumps may be difficult. And if the radiator has a pinhole, that could be an expensive and time consuming repair.

Anything made for "overclocking PC's" may work but require a lot of adapting as we know Apple likes to make things proprietary.

Last thing I will say is that if you replace the coolant in the unit, another task worth thinking about is how best to coordinate reducing the amount of air you end up with in the system.

iMic
13th February 2014, 10:31 PM
That G5 looks pretty stuffed. Even if it's repairable it'll be unlikey to still be a 2.7GHz model if the LB and processors have been replaced.

I'd concentrate on the 2.5 instead.

The cooling units are interesting. The main problems I see is that coolant attacks plastic and rubber over time (as it does in cars). The plastic parts of the unit will be degrading with time. You can probably quite easily replace hoses and hose clamps but the actual pumps may be difficult. And if the radiator has a pinhole, that could be an expensive and time consuming repair.

Anything made for "overclocking PC's" may work but require a lot of adapting as we know Apple likes to make things proprietary.

Last thing I will say is that if you replace the coolant in the unit, another task worth thinking about is how best to coordinate reducing the amount of air you end up with in the system.


Depending on how we go, it's possible that multiple G5s will be getting repaired. I could also possibly sell some of the more incomplete units for case mods to finance the repair of the more complete units, but I'm looking into that.


The Former-2.7 appears to have been down-converted to a June 2004 Logic Board with dual 2.0GHz processors. This makes the machine somewhat more repairable since it doesn't appear to have its stock (damaged) Logic Board or processors, and while it's missing its Graphics Card, I can use the FX5200 I already have from a previous failed G5 build plus an ATI Radeon X800 Pro PC card that appears to be based on ATI's reference design and may be flashable with the X800 Mac ROM. I think at the very least I'll shelve the unit and aim to repair it down the track, or keep the components out of it for use in another G5.


The Quad should be a runner off the bat, but it has an ACBel 1000W PSU in it, so not only is it incredibly power hungry - it's also in the affected range for the Power Supply REP and I'm not sure if the supply was replaced or not. Still - it's better than the Liteon. In terms of having a machine to play with, one of the Air-Cooled units would be nice since it's a little less intense with its power consumption.

I removed and inspected the liquid cooling system in the Quad 2.5. No leaks, no crystals around the CPU dies. Great base to build from. Possibly an already refurbished and repaired unit (it was used in an AASP service department since new), but I don't have any AppleCare service history for this machine. Haven't powered it up yet since I don't have the required power cable.

midnight_e
13th February 2014, 11:22 PM
Judicious sanding of the edge of the round iMac G5 plug will give you the rectangular PowerMac G5 plug if you are so inclined.
Found it easier to source the round plug than the proper one.
Used an electric belt sander.

iMic
14th February 2014, 07:15 AM
The problem isn't the physical shape of the plug, rather the pins and the amount of current the cable can safely handle. I'd need to source a Late 2005 power cable, like so, but with an Australian plug on the outlet end.

http://s27.postimg.org/r9bqn9j3n/922_6782.gif

Thankfully I have a lead on one that I may be able to pick up nearby.

Oldmacs
14th February 2014, 07:46 AM
A lead on one.. I see what you did there ;)

midnight_e
14th February 2014, 08:02 AM
I did wonder if the G5 power cables have different ratings.
Don't all G5 cables come in that variety you have pictured ?

I did that sanding bit on an iMac cable to work with a G5 that came sans power lead.
But it did seem a little lighter at the time, and I wondered if the power rating was different.

iMic
14th February 2014, 08:12 AM
I did wonder if the G5 power cables have different ratings.
Don't all G5 cables come in that variety you have pictured ?

Only the Late 2005 models with the 1kW power supply required that higher rated cable, iirc. All other G5s use a standard PC power cable (or "kettle cord").



A lead on one.. I see what you did there ;)

Friday Clearance. All puns must go.

midnight_e
14th February 2014, 08:44 AM
Only the Late 2005 models with the 1kW power supply required that higher rated cable, iirc. All other G5s use a standard PC power cable (or "kettle cord").

Sorry, not right.
Yes I think my late 2005 2GHz Dual core machine has a higher rated cable, this is the one that I remember as feeling thicker.
But I also have a 1st gen G5 1.6GHz, and a mid or late dual processor 2GHz, both have that particular cable you had an image of, certainly not a kettle cord.

Ha, just realised, a kettle cord cable could probably be used in those two earlier machines.
And yes just checked. Of course they would have come with the apple designed version, white and fits in flush.
Apologies ....

iMic
14th February 2014, 07:18 PM
No worries. For reference, the corroded machine above is a Dual 2.0GHz (was formerly a 2.7GHz) with a 600W PSU, and I have a Single 1.8GHz here as well that takes a 430W PSU. They both take IEC 60320 C13 connectors like so:

http://s27.postimg.org/hdau9rz0f/100px_IEC_60320_C13_svg.png


Where as the 1kW supply from the Quad takes the C19 style connector:

http://s27.postimg.org/tf166t1xb/100px_IEC_60320_C19_svg.png


Apple's technical documentation states that the C19 style power cable is exclusive only to the Power Mac G5 (Late 2005) system. All other G5s used the C13 connector (standard PC power cable).

Byrd
14th February 2014, 09:16 PM
15A/C19 cable is available at Jaycar or Radio Parts

iMic
8th March 2014, 12:25 AM
A friend of mine from a local AASP found a spare Apple genuine C19 power cable and donated it to the cause, so the Quad 2.5 is now a running machine. Cosmetically it's fairly rough, but it powers on and boots without any issues. Apparently it has a processor issue that causes the machine to lock up from time to time, but I haven't seen it since reseating the processor cards.


Due to the power consumption of the Quad G5, it doesn't receive much use. So I've been considering pressing on with repairing the Dual 2.0GHz machine as well, but since it requires extensive repairs, I've tossed out the idea of keeping it even remotely original. Since I'm working to a budget of almost nil, it means most if not all of the components will need to be fabricated in-house.

I removed the PSU and shelved the PCB. I'll scavenge that supply for its wiring harnesses, plugs, fans, capacitors and various other bits and pieces for the electronics box later. With the PSU out, the case was free of its rust and corrosion. I used a rotary tool to sand away some of the rust on components like the lower shelf and set those aside for later use.

The factory PSU has a combined output of 600W. Of that amount, 25V / 5.2A or 130W is allocated to ADC power. Since the machine will no longer have ADC, it's not necessary to take that amount into account when replacing the power supply. The Antec 550W that will likely end up in the machine exceeds the maximum ratings of the 3.3V and 5V rails, while falling only slightly short on the 12V and 5V Standby rails. However for the maximum safe ratings on those rails to be exceeded, the machine would almost have to be beyond fully loaded. I've heard of lower quality 550W units safely driving these units before, so I think this will be fine.

Since I kept the wiring harnesses from the factory PSU, it should be possible to make an adapter harness that will allow the ATX PSU to function in the G5 without irreversibly modifying either the G5 or the ATX PSU.

That leaves the missing front fan assembly. I'm not sure what solution I will use to address this issue. I have a single fan assembly, but it will only move air over the upper CPU. Perhaps I could modify this assembly to include a second fan for the lower CPU.

midnight_e
8th March 2014, 08:53 AM
Liking this thread iMac.
I have a G5, either 1.8 or 2.0 dual processor that was always flakey, would boot sometimes, others not.
Long time since I've looked at it.
Always thought may do a hackintosh machine using the case.