It is the dual bump "version 2" LCU. I had to take it apart and replace all the tubing, fittings and clamps. My CPU cards look identical to the images in your guide and I'm sure it'll work. If I remember right the "version 2" LCU was made in response to the original unit leaking.
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Comprehensive Guide to Converting G5 Quad to Air Cooling
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I've done some preliminary fitting of the parts and everything looks to be good. When it comes to using the included knurled thumb bolts from the coolers to attach the bracket to the motherboard standoffs I had an idea. What about the tall "bolts" used to secure the original cooler to those standoffs? They screw all the way down and they might just clear the fan. If they don't work I'll used the knurled ones. All I have to do now is go to the hardware store and make those holes bigger on the 2 front brackets. Hopefully it's all gravy from there.
I included more images of things. Feel free to include any of these in your guide and I'll be taking more throughout the process if I think they'll be of help to someone else doing this.
Don't worry I was very careful when setting the cooler on the CPU.
I'm sure this would be considered blasphemy by Apple purists... but it'll extend the life of the machine another 20-30 years until the thermal paste should be reapplied. Damn I'll be approaching retirement by then!
I included more images of things. Feel free to include any of these in your guide and I'll be taking more throughout the process if I think they'll be of help to someone else doing this.
Don't worry I was very careful when setting the cooler on the CPU.
I'm sure this would be considered blasphemy by Apple purists... but it'll extend the life of the machine another 20-30 years until the thermal paste should be reapplied. Damn I'll be approaching retirement by then!
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There have been some issues and the machine is unable to post or chime. When pressing the power button with air baffle off LED 3 and 4 are lit. LED 5 never comes on. I've noticed the infamous checkstop LED start to flicker rapidly a couple seconds after pressing the power button. It's not blinking but flickering with varying intensity. Almost like it's not sure what it wants to do. All fans come on as expected including the GPU fan. The LED above the power button doesn't blink at all but stays lit. The caps-lock on the keyboard works and the mouse has power. Here is everything I've done to troubleshoot...
1. reset the logic board via the button on the board.
2. remove all but innermost pair of RAM
3. remove all RAM (power LED above power button doesn't flash once indicating no RAM)
4. removed the CPU cards/heatsinks and verified pins are OK
5. powering on with no CPUs causes LED 1 and 6 to light up
I found a post on these forums about the checkstop LED blinking in defined groups of 2 meaning CPU B is dead. Mine comes on bright then flickers out. I hope the previous overheating and dark crud blocking coolant flow didn't kill CPU A.
My question is this: Could I move CPU B to the top slot and leave the bottom slot empty? Or will LED 6 come on and not post? Suppose I could also try swapping the CPU cards and see if checkstop blinks twice.
1. reset the logic board via the button on the board.
2. remove all but innermost pair of RAM
3. remove all RAM (power LED above power button doesn't flash once indicating no RAM)
4. removed the CPU cards/heatsinks and verified pins are OK
5. powering on with no CPUs causes LED 1 and 6 to light up
I found a post on these forums about the checkstop LED blinking in defined groups of 2 meaning CPU B is dead. Mine comes on bright then flickers out. I hope the previous overheating and dark crud blocking coolant flow didn't kill CPU A.
My question is this: Could I move CPU B to the top slot and leave the bottom slot empty? Or will LED 6 come on and not post? Suppose I could also try swapping the CPU cards and see if checkstop blinks twice.
LED diagnostic indicator chart.
If you're not seeing LED 5 either your logic board is bad or the CPUs are so cooked that it checkstops before finishing power on tests (reaches Open Firmware).
I'm thinking CPU A is dead. It overheated before so it makes sense. Can a quad technically run with only 1 cpu installed?
I have the January 13 2006 edition of the service manual
I have the January 13 2006 edition of the service manual
What are the results with the air baffle *in*? It makes a difference!
Quads CAN run on just one CPU card, since you can turn off the second one via an Open Firmware command. However, I *think* the second one has be somewhat "sane" to even get to the Open Firmware prompt to disable it...sort of a Quad "Catch-22" .
I am presently running my Air Quad with CPU B disabled because it was causing color artifacts on the display. I must have "lightly damaged" it during the combination of LCS and Air cooling efforts. It runs, but it causes random, and sometimes severe, color distortion on screen, so I turned it off.
The Quad runs wonderfully on just one CPU card (2 cores) and correctly, if somewhat humorously, reports itself as a Dual 2.5 GHz machine in "About This Mac". I prefer to think of it as a "Half Quad"!
Quads CAN run on just one CPU card, since you can turn off the second one via an Open Firmware command. However, I *think* the second one has be somewhat "sane" to even get to the Open Firmware prompt to disable it...sort of a Quad "Catch-22" .
I am presently running my Air Quad with CPU B disabled because it was causing color artifacts on the display. I must have "lightly damaged" it during the combination of LCS and Air cooling efforts. It runs, but it causes random, and sometimes severe, color distortion on screen, so I turned it off.
The Quad runs wonderfully on just one CPU card (2 cores) and correctly, if somewhat humorously, reports itself as a Dual 2.5 GHz machine in "About This Mac". I prefer to think of it as a "Half Quad"!
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I haven't worked on it just yet. CPU A likely died when my rebuilt LCU got gummed up with something. This weekend I'm gonna move CPU B to A and see what happens. If it refuses to work with nothing in the B position I'll put CPU A in and see what that does. If it boots with the CPUs reversed and is stable (unlikely) I'll leave it. However, if it has issues and I can at least get into Open Firmware I'll have to disable it.
I'm also trying to figure things out at 68kmla.org with regards to a replacement CPU.
The actual process of doing the air mod did go smoothly and i'm going to try something different. instead of using 3/16s worth of spacers in the front i'll try the same 1/4" thick spacers like the back. And try not cutting myself again on that thin metal along the PCIe slots while plugging in the rear fan.
I'm also trying to figure things out at 68kmla.org with regards to a replacement CPU.
The actual process of doing the air mod did go smoothly and i'm going to try something different. instead of using 3/16s worth of spacers in the front i'll try the same 1/4" thick spacers like the back. And try not cutting myself again on that thin metal along the PCIe slots while plugging in the rear fan.
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Yup! That thin metal slot protector is a *killer*!
Can you buy *just* Quad CPU cards (not whole Quads) through 68kmla.org? I need one as well!
Can you buy *just* Quad CPU cards (not whole Quads) through 68kmla.org? I need one as well!
68kmla is another place like here to get help. Sometimes you just gotta widen your net to get answers and combine everything into a solution that (hopefully) works.
BTW, @amishallin, did you have any luck with the tall "bolts" as fasteners? I tried them, but found that they would not "bite" onto the threads of the alignment posts with the FROZN mounting brackets also on those posts. If they would have screwed down, they would have been a perfect solution.
This may be a silly question, but are you sure that the FROZN/shim sets are tightly screwed down onto the CPUs? If they are not, it could explain some of the behavior you are seeing. Perhaps CPU B is tightly screwed down but not CPU A? I had all nature of problems until I came up with the "knurl" solution and accomplished a tight fit of the cooling apparatus onto the CPUs.
One other thing to examine: It *looks* like you assembled each CPU card/shim/FROZN cooler set before installing them into the Quad. Did you also attach the fans to the FROZN coolers before installing each CPU card? If so, is it possible that the second CPU/shim/FROZN/Fan set, after being installed, exerted mechanical pressure on the first one installed, pulling it even slightly off its tight fit onto its CPU? Mechanical clearances are really tight in that area... @Doq mentioned a similar issue in his post on air cooling his Quad.
This is why I used the FROZN clips on the top CPU fan, but only duct tape (and a twist tie) on the second one, so that it fit into the case without pressing on its peer CPU card fan in any way.
Assuming they are both tightly screwed down, and not impinging on each other, your plan to swap the A and B CPU positions seems the right next step. I am about to try the same thing on my LCS cooled Quad, which won't boot at all right now - the Check Stop light comes on immediately. I am hoping that CPU B is still operational (it is unlikely that both CPUs got "smoked"), and when placed into the A slot, it may provide enough "brains" to get the Quad up to Open Firmware, where I can disable the second CPU.
Stay at it @amishallin! Persistence and determination are the keys to success in this effort. I had nothing but trouble until I came up with the "knurl solution", but it was the third or fourth thing I had tried - until then, it was just one failure after another. I just kept methodically plugging away at it until I finally succeeded. The result is SO worth it! A "cool, quiet Quad" is a thing of beauty!
[offside comment]
The alliterative nature of "cool, quiet Quad" always puts me in mind of a line from the Pink Floyd album "Dark Side of the Moon", which talks about a "short, sharp shock". I made reference to this in one of my posts, but no-one seemed to notice, or to comment anyway!
[/offside comment]
In the end, the only thing that can truly stop you is dead CPU cards. As I said in my guide, it is "game over" if you kill the CPU cards. If that happens, you have to pause until you can source replacement CPU cards, something I have not yet been able to do. Hence, my Air Quad runs on two of its CPUs, not four, because I damaged one of the CPU cards somewhere along the way. Mind you, even a "half Quad" is amazingly fast!
This may be a silly question, but are you sure that the FROZN/shim sets are tightly screwed down onto the CPUs? If they are not, it could explain some of the behavior you are seeing. Perhaps CPU B is tightly screwed down but not CPU A? I had all nature of problems until I came up with the "knurl" solution and accomplished a tight fit of the cooling apparatus onto the CPUs.
One other thing to examine: It *looks* like you assembled each CPU card/shim/FROZN cooler set before installing them into the Quad. Did you also attach the fans to the FROZN coolers before installing each CPU card? If so, is it possible that the second CPU/shim/FROZN/Fan set, after being installed, exerted mechanical pressure on the first one installed, pulling it even slightly off its tight fit onto its CPU? Mechanical clearances are really tight in that area... @Doq mentioned a similar issue in his post on air cooling his Quad.
This is why I used the FROZN clips on the top CPU fan, but only duct tape (and a twist tie) on the second one, so that it fit into the case without pressing on its peer CPU card fan in any way.
Assuming they are both tightly screwed down, and not impinging on each other, your plan to swap the A and B CPU positions seems the right next step. I am about to try the same thing on my LCS cooled Quad, which won't boot at all right now - the Check Stop light comes on immediately. I am hoping that CPU B is still operational (it is unlikely that both CPUs got "smoked"), and when placed into the A slot, it may provide enough "brains" to get the Quad up to Open Firmware, where I can disable the second CPU.
Stay at it @amishallin! Persistence and determination are the keys to success in this effort. I had nothing but trouble until I came up with the "knurl solution", but it was the third or fourth thing I had tried - until then, it was just one failure after another. I just kept methodically plugging away at it until I finally succeeded. The result is SO worth it! A "cool, quiet Quad" is a thing of beauty!
[offside comment]
The alliterative nature of "cool, quiet Quad" always puts me in mind of a line from the Pink Floyd album "Dark Side of the Moon", which talks about a "short, sharp shock". I made reference to this in one of my posts, but no-one seemed to notice, or to comment anyway!
[/offside comment]
In the end, the only thing that can truly stop you is dead CPU cards. As I said in my guide, it is "game over" if you kill the CPU cards. If that happens, you have to pause until you can source replacement CPU cards, something I have not yet been able to do. Hence, my Air Quad runs on two of its CPUs, not four, because I damaged one of the CPU cards somewhere along the way. Mind you, even a "half Quad" is amazingly fast!
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I had the same results as you did with those tall bolts and used the knurled ones.
Its not really a silly question. I imagine if the coolers weren't tight enough they may not make good contact and cause them to overheat. However, if they were too tight they may cause damage considering the spacers near the rear are 1/4" and the ones in the front are about 3/16." This is why I want to try having all spacers be 1/4" and have a more even pressure. Currently, I have nylon spacers/washers since that's all my hardware store has other than metal. How tight did you screw yours down? The screws that connect the cooler to the brackets have springs for tension. I could technically go tighter but they're about as tight as the liquid cooler (has springs for tension) on my AMD 7950X3D gaming PC that never reaches 60C running 24/7 at flat 94% CPU utilization crunching numbers for milkyway@home. I also don't wanna crack a trace or solder joint on the board.
There are things I'm going to try this weekend and hopefully have a booting G5 even if with 1 CPU installed.
Its not really a silly question. I imagine if the coolers weren't tight enough they may not make good contact and cause them to overheat. However, if they were too tight they may cause damage considering the spacers near the rear are 1/4" and the ones in the front are about 3/16." This is why I want to try having all spacers be 1/4" and have a more even pressure. Currently, I have nylon spacers/washers since that's all my hardware store has other than metal. How tight did you screw yours down? The screws that connect the cooler to the brackets have springs for tension. I could technically go tighter but they're about as tight as the liquid cooler (has springs for tension) on my AMD 7950X3D gaming PC that never reaches 60C running 24/7 at flat 94% CPU utilization crunching numbers for milkyway@home. I also don't wanna crack a trace or solder joint on the board.
There are things I'm going to try this weekend and hopefully have a booting G5 even if with 1 CPU installed.
Can confirm this is what happened. With the clips installed the cooler becomes just barely too wide to install side-by-side and cooling contact suffers if the processor card itself isn't poorly seated.
Used to be one clip per cooler on the outside edges with a twist tie but I've replaced the twist tie with a more elegant 3D-printed solution instead.
In regards to screw tightness, I don't know how much tension @mac57mac57's install can get, but in my install I actually was able to bottom out both the captive screws on each end of the cooler itself and the pass-through screws with the thumb-nuts.
I wouldn't worry too much about cracking traces or solder joints (the processor board's PCB is pretty robust), I'd be more concerned with cracking the 970MP's die itself, since you are cooling a bare die and run that risk.
Thanks @Doq, I tend to agree that you can apply as much mechanical tightening to the mounting hardware as it will take. However, I was more "measured" when I did this. The FROZN mounting screws in my Air Quad are probably about half way tightened down.
I am ALWAYS, just as a matter of course, cautious about over tightening heat sinks on any CPU card: Mac or PC - you can literally squeeze the thermal paste out, reducing cooling efficiency substantially.
So... I tightened mine incrementally, a little bit at a time, alternating between front and back, until I could feel that the cooler was tightly seated. I am guessing that this was about half way in each case, but that IS a guess.
I am ALWAYS, just as a matter of course, cautious about over tightening heat sinks on any CPU card: Mac or PC - you can literally squeeze the thermal paste out, reducing cooling efficiency substantially.
So... I tightened mine incrementally, a little bit at a time, alternating between front and back, until I could feel that the cooler was tightly seated. I am guessing that this was about half way in each case, but that IS a guess.