iMac G4 20in NUC mod - CelestialTower

[muk546]

Update:

Well I've got my power solution finished:

PWR1.jpg

I was very confused on what to do but this solution seemed the easiest and most obvious to me...

What I did was take the original receptacle output wires and I cut the wires and used a female AC receptacle then a Male to 3 Female 3 Prong receptacle unit all rated for 15A 125V High Quality from home depot. The result:

PWR4.jpg

Works 100% tested with my cheap-o multimeter reads 117.4V (120v) with this I can use separate power bricks and internalize everything with the original power cord! (Yay)

PWR5.jpg

Now I don't have to worry about using the original iMac's power supply as a pico and the original NUC one's will suffice!

 

[ersterhernd]

Hi muk, does the dome still close up ok? Those are large plugs. I cut, spliced and soldered all my AC lines using the least amount of wire I could, and it was still tight for space...


Cheers!

 

[muk546]

Your right!

Looks like I'll just splice the two bricks right into the A/C line. At this point I'm pretty sure I'm going to have to either give up the case fan or the optical drive, most likely the DVD drive because cooling is more important.

 

[muk546]

Major update:

I'm almost done ill have a walkthrough of what i did soon and a video of the working unit i'm currently getting ready to close it up!

 

[muk546]

I have one problem yet to solve the Pico PSU does not work reliably with my step up converter any ideas why? anyone?

the orange light briefly flashes (with slight buzzing sound) but works fine without the step-up and the weird thing is i can force it to work via touching the green and (PWR ON) and black (Ground) wires while the PSU is live then it works fine but isn't safe to do repetitively.

Any thoughts?

Im using a wide-input 120w pico psi with a 19v 90 watt brick all this thing needs to do is power the LCD a case fan and a usb hub nothing else 90W is enough! Right?

 

[ersterhernd]

Hi Muk, the step-up converter is likely causing a amperage spike on the pico at startup and the unit is shutting down with built in self protection. I had this problem with my iMac G5 20" project, that used the same step-up converter as the 20" G4.

I solved it by connecting the thick 12V and GND wires out of the step-up converter to smaller gauge wire first before plugging into the pico. This limits the current out of the pico to the step up converter, and thus solved the issue.

It took a few days of grief to figure this out, however. Whether this is the issue with yours, I'm not sure, but certainly worth a try.

Good Luck.


Ersterhernd

 

[muk546]

Thank You!

That did the trick! I can now solder everything down and call this just about done!

 

[mitchellaneous]

Hi, I don't mean to hijack your thread, but it was the most recent active thread for this build and I wasn't sure if my question warranted its own thread.

Anyway, I'm about to start a 20" NUC build myself. At least at this point, I'm planning on using the native PSU, pretty much how jberg/Dremel Junkie has it set up on his site. However, I'm planning on using the Haswell NUC board, and while looking at the pinouts for the headers I noticed that there's more than one source of 5v straight from the board itself. There's a pin in the FP header that supplies 5v, as well as the onboard SATA power plug, which doesn't push 12v so I wouldn't be using it anyway. Would either of these be okay to use to provide the PSU the 5v it needs to activate the 24v line to the LCD inverter (and my PicoPSU), instead of adding another splice to the DVI VEDID?

 

[kiwisincebirth]

Hi, I don't mean to hijack your thread, but it was the most recent active thread for this build and I wasn't sure if my question warranted its own thread.

Anyway, I'm about to start a 20" NUC build myself. At least at this point, I'm planning on using the native PSU, pretty much how jberg/Dremel Junkie has it set up on his site. However, I'm planning on using the Haswell NUC board, and while looking at the pinouts for the headers I noticed that there's more than one source of 5v straight from the board itself. There's a pin in the FP header that supplies 5v, as well as the onboard SATA power plug, which doesn't push 12v so I wouldn't be using it anyway. Would either of these be okay to use to provide the PSU the 5v it needs to activate the 24v line to the LCD inverter (and my PicoPSU), instead of adding another splice to the DVI VEDID?

I haven't done, a IMac G4 conversion, but have used the NUC in a build, so can answer your questions. So YES you can use either 5V source on the NUC with two caveats.

1. Power Rating - How much power do you need to draw ? Remember the connectors on the NUC were designed for specific purposes, and trying to draw more power could damage the NUC. The SATA port should be able to provide more power, as it is designed to power a 2.5" HDD.
2. When is it on - The different connectors may provide 5V power at different times, so depending on your need one may be better than the other. SATA port may not (theory) provide power all the time you would need to test this.

There is another port on the Haswell NUC that provides standby 5V, so is powered regardless of wether the NUC is on or Off

Hope this helps.

 

[mitchellaneous]

I haven't done, a IMac G4 conversion, but have used the NUC in a build, so can answer your questions. So YES you can use either 5V source on the NUC with two caveats.

1. Power Rating - How much power do you need to draw ? Remember the connectors on the NUC were designed for specific purposes, and trying to draw more power could damage the NUC. The SATA port should be able to provide more power, as it is designed to power a 2.5" HDD.
2. When is it on - The different connectors may provide 5V power at different times, so depending on your need one may be better than the other. SATA port may not (theory) provide power all the time you would need to test this.

There is another port on the Haswell NUC that provides standby 5V, so is powered regardless of wether the NUC is on or Off

Hope this helps.

Thanks for the reply. I hadn't considered how much power it'd draw from the board but I doubt it'd be much. I can test this the next time I pull the G4 apart. As for the second point, I only need it to provide voltage when the board is actually on, in fact I definitely don't want the 5v going to the PSU when the NUC is off or asleep so the 5v standby on the Custom Solutions header will definitely not work (for my purposes anyway). Once I actually have the NUC I can test again to see when each source actually provides the voltage I need.

Also, even though I don't have any plans to pick up and/or mod a iMac G5 anytime soon, I've been following your build thread as well. It's great work and I might try to incorporate some of your ideas into the G4 I'm going to be working on, mostly the microcontroller setup (though only for the startup chime and LCD brightness control), and soldering the HDMI socket to the LCD cable. Both of these may be beyond my capabilities but I do have a spare 17" G4 sitting around in case I screw things up TOO badly. I'm probably getting in over my head but it won't stop me from trying.