G5 Quad won't boot (and 2.7DP smells of fire)

[TitaniumFrog]

So, I recently was given a G5 Quad and a G5 2.7DP. Lo and behold, the Quad boots - well, somewhat.
I once got to a login screen, but had no USB ports functioning. I then went to the process of resetting NVRAM/PRAM using command+option+P+R. That worked, at least I got two bongs, but boot process didn't change.
Then I reset the PMU and replaced the CR-2032 battery, that didn't help much either. Then I reseated RAM and GPU, and now I have a different kind of message in verbose mode.

When I boot either from HDD or retail 10.5.1, I get stuck at a message that "nvdanv40hal" has been loaded in, and that's it. A while later, USB stops functioning (in that no caps lock switch on the kb, but the mouse has power) and the fans go haywire for a bit, only to ramp down again.

Now when I boot from HDD without verbose, I end up with a blueish screen with a mouse in the top left corner that I cannot control and from there it hangs.

Any suggestions on what to test next? I don't have a GPU handy to replace it with, sadly.

Oh and I guess the 2.7DP leaks, 'cos I think there's some salt deposits and I heard and smelled ungodly things when I booted it up. So I'll leave that off for now.

 

[TitaniumFrog]

Alright, there's a little progress.
I managed to boot ASD 2.6.3 and found out that if I grab my old Apple keyboard with USB ports and connect a mouse to it, I get a working mouse - so yay that.
I started the CPU tests, and found that these tests make the Mac hang. There is power to USB, but no acceptance of input. Furthermore, I see LED #7 Checkstop lit up, but that's it. No CPU temp or something like that.

My hunch is now that one of the CPUs may either be not seated correctly, may be defective or some traces have given up. I think this entails taking out the entire assembly and assessing it for damage or something like that. The fact that I don't get thermal shutdowns gives me hope that at least the cooling sort-of works.

If anyone knows some other tests I could perform, please let me know.

 

[TitaniumFrog]

Welcome to part three of taming the Quad!

So, once again there's been a little progress. The Mac was completely disassembled up to the motherboard logic board, because I don't have a 9/32" imperial socket. The case is a bit rough, the dust had been sitting for so long that the finish turned somewhat less smooth. It's clean now, all the dust is off - though I wonder how many forms of airborne diseases I have inhaled... Oh well!

Most importantly, there was no leakage of the single pump Delphi to speak of. That said, there are signs that the leaking has begun:
- Acid/corrosion deposits on the screws holding the cold plate to the assembly:

- Sloshing about of liquids, there's clearly lots of air inside

So, the next steps are as follows:
- Fix myself a 9/32" imperial socket (easy)
- Fix myself a rounded/ball Inbus 4 to properly put back the screws of the cooling assembly (easy)
- Fully disassemble the case, remove and clean everything (doable)
- Disassemble PSU, inspect caps and test them (together with a senior electrical engineer, 'cos I'm an idiot without a death wish) (doable)
- Revise the LCS (lol help, any good info on revising the single pump Delphis? I can mainly find dual pump guides. For now I'm using this: https://www.h-lindholm.net/articles/g5-quad-lcs-repair/g5-quad-v1-lcs-repair.html)
- Rebuild the bastard, possibly offer a virgin Snow Leopard disk to Steve Jobs.

Furthermore, I read somewhere that the plastic tab holding in the G5 shield over the LCS is required for the functioning of the Mac, is this true?

On a sidenote, someone is giving a 1.8 GHz PCI G5 (Late 2004) which is missing some parts - luckily I still have that nasty 2.7GHz DP hanging around. I'll take out what I need and then clean it up as well as I can (I need an HDD and RAM. And possibly a RAM locking tab, there seems to be one missing.) That seems to be it.)

One day I'll have at least one working G5. One day...

 

[TitaniumFrog]

Nearly a full year later...
I sold the 2.7 DP to someone who wanted the case, I didn't have the interest to fix it up.

I now have 3 Quads!
1. The one mentioned above
2. One that sometimes gets to the Apple-logo, but then checkstops and shows the prohibited sign. Once got the overheat LED, so I suppose that makes sense.
3. One that keeps checkstop lit all the time, doesn't gong, doesn't make noise when there's no RAM installed. Seller did the water pump and as far as I can see the water doesn't move either when it reaches checkstop. So something seems to be quite wrong there.

Current idea:
Reseat the CPUs in from 3. If that doesn't work, move the CPUs to 1., as it still has its CPUs out. If that doesn't work, take 1.'s CPUs and put them on the refreshed cooler of 3. I know those CPUs work.

If you have any other ideas or suggestions, please let me know! These are finniky machines, but I'm very well set on making at least one work.

Of these three, I hope I can build one working Quad. That's three motherboards, three PSUs and six CPUs. Seller also sold me a brand new Delphi pump and hoses/clamps etc, so I'll be flushing the 2 non-flushed systems soon.

 

[ToniCH]

Revise the LCS (lol help, any good info on revising the single pump Delphis? I can mainly find dual pump guides.

Yes, that seems to be the problem. My both Quads are single pumps, haven't found much how-tos on those. But, I guess it should be simpler than the twin pump -setup?

Do you know if the pumps are the same format on both setups? I would like to do the "new blood" mod with the clear acrylic pump cover and hoses but not sure if the cover will fit the single pump Delphi-pump. Waiting for the parts so I guess I will find out when I'll try it.

 

[TitaniumFrog]

Yes, that seems to be the problem. My both Quads are single pumps, haven't found much how-tos on those. But, I guess it should be simpler than the twin pump -setup?

Do you know if the pumps are the same format on both setups? I would like to do the "new blood" mod with the clear acrylic pump cover and hoses but not sure if the cover will fit the single pump Delphi-pump. Waiting for the parts so I guess I will find out when I'll try it.

I did some research on which pumps were used when. Though I couldn't find definite numbers, I found this:

All versions of the Power Mac G5 Quad LCS units use Laing DDC pumps. The same Laing models were also generally available from stores selling PC water cooling supplies at the time of the G5's introduction and some years after. The specific models that were used included Laing DDC-2 (DDC2B-VC), DDC-3.1, and DDC-3.2. All pump models in the G5s were equipped with the Volume Compensator (the -VC suffix in the pump model specifier), which was/is only available to OEMs.

The older Power Mac G5 Dual machines with Delphi LCS units also utilized Laing DDC pumps. The older generation Delphi unit had Laing DDC-1 pumps (DDC1-VC and DDC1A-VC). The volume compensators in some of these pumps were prone to diaphragm breakage and leaking.

The DDC-1 and DDC-3.1 models were lower powered at 10 W and max 3900 rpm while the DDC-2 and DDC-3.2 models were higher powered at 18 W and max 4500 rpm. In practice, DDC-2 was the highest powered model with higher head pressure than the other models, but it also had the highest failure rates. The DDC-1 pumps had black impellers, the DDC-2's orange or brown, and the DDC-3's blue ones. In all the Apple LCS units, the rpm was limited to max 3600, so the pump's version did not actually matter.

The Laing DDC-1 and DDC-3 models had different electronics and signalling and are not interchangable. The tachometer signal in the DDC-1 models has 12 pulses per revolution whereas the in the DDC-3 models it has 2 pulses per revolution. The speed control scheme is, apparently, also different. The DDC-3.1 and DDC-3.2 are essentially the same pump: the DDC-3.2 has one connection bridged compared to the DDC-3.1, yielding a higher powered pump. The DDC-2 and DDC-3 models are interchangable, but the wiring order on the PCB is the exact opposite.

The current Laing DDC models, somewhat confusingly named DDC-1T, DDC-1+, and DDC-1RT, have new design and are no longer compatible with the Power Mac G5 signalling. The newer pumps can be driven by the G5, but the speed control scheme is yet again different, and therefore the PWM pin of the newer pumps should be left unconnected.

The Laing pumps are and were also sold as Swiftech MCP350 and MCP355. The MCP350 was/is equivalent with the Laing DDC-1, DDC-3.1, and the newer DDC-1T models and the MCP355 with the Laing DDC-3.2 and the newer DDC-1+ models.

Source: https://c5zea5gd.c5.suncomet.fi/articles/g5-quad-lcs-repair/g5-quad-v1-lcs-repair-pump.html

If I then look at the compatibility specs of the Alphacool Eisdecke DDC V.4 Acrylic Top that's used in the New Blood Mod, they state:

Now you should unpack your replacement pump top. I used an Alphacool Eisdecke V.4 because I figured out it is a perfect fit, with the caveats mentioned above. Your pump top needs to be exactly the same height as the Alphacool model or smaller. There is no wiggle room at all here. The replacement tops are as big as they could possibly be.

In other words, this replacement top seems to be a 1:1 replacement for all Laing DDC pumps. I don't have any experience so I cannot confirm anything for sure, but given the information above I'm willing to say that you have a very good chance indeed to get it all fitting.

 

[ToniCH]

Yeah, when I was ordering the parts I looked at the Laing-pumps that are listed to be compatible with the acrylic top. They indeed seem visually very similar than the original Apple/Delphi pumps.

But I didn't order a new pump as I read somewhere that the new aftermarket pumps and G5 communication is not compatible and the G5 does really not like the Laing pumps available now. EDIT: ah, this stuff was explained in the quote you posted.

Anyways, lets hope the acrylic top also fits the stock single pump and seals too. We shall see. I should get the parts this week but don't know yet when I can tackle the cooler overhaul. I do have a 6ltr ultrasonic cleaner but lets see if the cooler fits inside or do I need to clean the crust out of it manually. Its still (again) winter here and I do not want to open and flush the cooler inside the house.

 

[TitaniumFrog]

I just reseated the CPUs on the 3. Power Mac Quad mentioned above. Exactly the same behaviour... I did notice the checkstop light flickering before it turned on solid. Furthermore, the pump doesn't even start up, so there's no 12V rail present (or the pump's buggered?). AFAIK if it doesn't get a tacho signal, it should just ramp up to full fan speed, it does nothing of the sort.

I also noticed the screws on the backside of the CPUs, connecting the CPUs to the coldplates, were pretty gnarly. Stripped, driven in with pliers and even sticking out somewhat, touching the black plastic underneath the tray on the logic board. Not sure how to go about that, really. I may just remove the CPUs and use screws from one of the other two Quads.

What did I learn from this

1. 't was not the CPUs that were not seated properly

I think it's best if I at the very least replace those screws first and then test these CPUs w/ pump in another machine, see what that does. Does anyone have experience with a checkstop at bootup and no working pump? Maybe it checkstops because of the pump, I'm not sure.

 

[ToniCH]

Hope you get it running. How did you notice/determine that the pump is not starting? Maybe try feeding it current from another source to see if the problem is with the pump or the G5?

Aaaaaand my parts suddenly arrived. Lots of small parts I do not yet know where they belong. So, the Eisdecke DDC plexi top v4, hose tail barbs, BitsPower Touchaqua air outlets and plenty of tubing + UV green dye to give color to the coolant to poison-green.

 

[TitaniumFrog]

Hope you get it running. How did you notice/determine that the pump is not starting? Maybe try feeding it current from another source to see if the problem is with the pump or the G5?

The seller revised the cooling, I guess that's why those screws are so mangled. One of the perks is that he used clear tubing. I don't see any airbubbles moving or do I feel the pump working. I indeed to have a bench PSU I could use, with a few small leads.

Aaaaaand my parts suddenly arrived. Lots of small parts I do not yet know where they belong. So, the Eisdecke DDC plexi top v4, hose tail barbs, BitsPower Touchaqua air outlets and plenty of tubing + UV green dye to give color to the coolant to poison-green.

Nice to hear! That should give you a proper chance at properly rebuilding your LCS, good luck!

 

[TitaniumFrog]

Small update: After not having done anything to it, the no 2. G5 trips the breaker. I can't see any leakage at all, but I'll have to take out the CPUs to be sure I think. Or the PSU has a blown cap, that could explain the iffy booting at first... Getting a bit annoyed with these bastards 😅