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Another G5 Build

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Sep 28, 2018
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Hello All, here is a series of pictures and a brief story on a G5 build I did last summer.

I scored one of these cases for 37USD +- plus an extra 1KW Apple PSU for free about 2 years ago. I originally thought of using the apple hardware that it came with but it was not booting. Also one of the power supplies was busted so I first sort out on fixing that. It was not much of a mission to fix, some of the Mosfet on the high side of the power supply went closed circuit (probably because some dust shorted them out). I just replaced them and just like that I had two 1KW Apples PSU's.

I firstly emptied the case of the old hardware and then installed a front I/O panel from theLaserhive.com (I am sure some of you know about this store), I also bought their mini ATX conversion kit from them.

The Mechanical Part

So my goal of this build was to keep the case as original as possible E.G original fans, Power supply and mechanical parts. Now I did wish to keep the original I/O panel but the one sold by the laser hive matches the case pretty well and I would not have to deal with soldering wires to the original panel.

Here is the case with the installed Kit and I/O panel and some of the cutting that was done to the case.

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The Power Supply

The Power supply has no standard connectors therefore if one wants to use the original power supply they would have to modify all the connections, so that is what I did.

Here is the original PSU with the cables I would need to solder to it.

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These massive connectors had to be removed, I bought a cheap 500 watt soldering Iron from Hornbach and it got the job done but it was not easy.

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After the original connectors were removed I began soldering in the new cables I had made. These two are power for the CPU and GPU (12V rails)

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Here I am testing the completed modification of the Power supply with a PSU tester (Note that these are really cheap devices and cannot be trusted so double check every connection with a Multimeter). Also note that this power supply does not have a negative 12V rail, So if you need it for any reason you will have to make an extra circuit to create that rail.

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And below is the completed modification. I know the cables look weird but they fit perfectly in the case with no extra cable lying around to make a mess

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Here is a quick shot of me measuring the lengths of the power cables.

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The Fan Controller and Temp Readers

Since I wanted to use the original fans that came with the G5 I had to make myself a custom circuit since you cannot simply plug them to an ATX motherboard. After doing some reading on the net I found the pinout of the fans and created a circuit that used 3x LM713 voltage regulators. These regulators have the ability to change the output voltage based off a feed back pin therefor changing the fan speed.

I also created a little "Amplifier " circuit to utilize the original speak that came with the case that would beep when the motherboard posts.

Another Part of the circuit was reading temperature from sensors around the case. I removed the original temp sensors and placed some Dallas 18b20 temperature sensor in their place.

All of these parts were then controlled by an Arduino Nano and would be connect to one of the internal USB header of the motherboard to receive the temp data and control fan speeds manually if need be.

The 18B20 sensors

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Here I was testing the fans with a bench Power supply (Note that these fans use a ton a current)

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Unfortunately two of the original fans were not running smoothly from all the dust they had collected over the years.

I replaced them with some standard 80 mm fans.

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Here I was testing the small amplifier I made for the speaker. The Red/Black wire is the speaker and the Red/White wire was the motherboard connection.

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Here I was test fitting the control box inside the case

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The inside of the control box. Those beefy heat sinks are for the power hungry CPU fans.

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Some not so nice wire management under the board ( I will eventually get a PCB manufactured to replace this)

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Here the controller is installed (That switch is for programming, in the case I am programming another Arduino for a project I do not want to accidentally program the Arduino inside the computer, the switch connects a capacitor to the reset pin of the Arduino disabling it from being programmed)

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Here you can see it fits perfectly underneath the front CPU fans.

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And for some final shots...

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System Specs

  • GTX1060 Founders Edition
  • Core i5-7500 3.4 GHz
  • Asus H170m-plus
  • 16GB RAM
  • 256 SSD M2
  • 2* 1TB in RAID 0
  • 1KW PSU
  • DVD/CD RW ROM
Unfortunately along this process I destroyed one of the Power supplies, but luckily I had another one. If any of you modify this power supply take extra caution when putting the PCB back into its enclosure. Some of those capacitors have 200 volts in them and if they touch the enclosure it could blow up some other part if its self, this happened in my case.

Any questions are welcome.

Byron
 
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Got some really nice touches in there. Loving the Arduino action and the re-purposing of the original PSU. Well done!
 
Very impressive mod especially for the PSU and fan controller; I also have a 1kw G5 pSU also wanna to reuse it to ATX, but don’t know how to test it before beginning to do the soldering, when I short the PS_ON pin with ground, the unit just click on and then off within 1 second, but this unit is confirm working because I just pull it from a working Powermac and The standby 5V is also measured ok, any suggestions? Thanks in advance and have a nice day!
 
Make sure you are not shorting out any of the rails. It sounds like the over current protection is tripping the relay. But that is just a guess. also try short the PS_ON to different ground points.

Maybe post a new thread with some photos if you need more help.

Byron
 
Make sure you are not shorting out any of the rails. It sounds like the over current protection is tripping the relay. But that is just a guess. also try short the PS_ON to different ground points.

Maybe post a new thread with some photos if you need more help.

Byron
Thanks for your suggestions! I just measured the output found a 0 resistance reading only for the V12A/V12B to the nearby ground pad, but there are no sign of short cause I just removed all the output wires and soldering Pad is cean also;how does it happen! I just have no idea about that.
 

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Wow, nice build! I am attempting to also mod a 1 KW G5 PSU into ATX compatibility. WHat resources did you guys use to find out the pin outs of the P2 and P1 connectors? I found some pinouts for older models. Are they the same?

Also, how often are the -12 V rails and -5 V rails used? I am considering to buy a converter to convert one or two of the +12 V/+5 V lines into -12 and -5 V rails.

So if I am reading the posting correctly, you created the Arduino board in order to control that fan speeds.

Would you be able to post some schematics for the custom board? And if possible the source code of the controller?
 
@youyoudeyou

Have a look if a rogue solder ball didn't short anything out. If nothing is found start looking at the capacitors, (maybe that yellow one would be a good place to start)

@philm001

There are no schematics as of yet and the source code is also none existent at the moment, currently the Arduino just sets all the speeds to default low.

As for how I controlled the fan speeds. I used an LM317 which is an adjustable voltage regulator. I then tied transistors to a set of different resistors and by activating a certain transistor I would effect the set voltage for the 317.

Below is an example from a website
LM317-voltage-regulator-digitally-selected-output.png


So I just chose A B C or D and that will define how fast the fans spin. But this is a really lazy approach, if you have time I recommend controlling the fans with PWM.

And as for the negative rails, they are not that important, some old communication ports used to have positive and negative rails but most of these ports are no longer used, although if they are not present the computer might not post, I personally did not run into this issue but it could arise.

Byron
 
Thanks for your advice, I take off the yellow one and all the 2200uf cap of the center 12v channel, all measured fine, also all the dido is also okey, plan to check the protection circuit itself but it’s hard cause no diagrams on internet.
 
@B-Unit

Great! Thank you for the information! Also, do you have a diagram on the pinouts for the P1 and P2 connectors?
 
ALso, to turn on the power supply when you press the power button, did you have to route one of the connections on P1/P2 to the power on pins for the ATX PSU pinout?
 
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