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An Amazing Find for My Next Project -- iMac G4 20"

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Hi MrDale, with your i3 NUC the build should be smooth. The i5 NUC graphics corruption issue caused me an immense amount of grief, and remained unresolved on the 20" LCD. You'll really enjoy the machine at completion, it's a dream to use.


Cheers!
 
Hi MrDale, with your i3 NUC the build should be smooth. The i5 NUC graphics corruption issue caused me an immense amount of grief, and remained unresolved on the 20" LCD. You'll really enjoy the machine at completion, it's a dream to use.


Cheers!

Another great mod! I'm following your iMac G5 mod, it's amazing how fast you move on to new mods! What I was wondering is how you mod the speakers, or at least get them to work with a 3.5mm connection. I have a pair at my house with a 17" iMac G4 800MHz, and I would really love to reuse them. Thanks!
 
Incredible to read through this whole thread.

Picked myself up a PERFECT iMac G4 20-inch USB 2.0 Model today for $80 with some bonuses (USB & bluetooth keyboards, DVI -> VGA adapter.) The machine looks fantastic, and I cannot wait to throw a NUC in it this summer. Unfortunate to hear that the HD5k doesn't want to cooperate, though an Ivy Bridge i5 NUC is significantly cheaper now, since it's last year's tech.

Hopefully, I'll be soon on my way to making a great machine like this. Always have been a big fan, E - can't wait to have my own iMac G4 mod.

-IC
 
Incredible to read through this whole thread.

Picked myself up a PERFECT iMac G4 20-inch USB 2.0 Model today for $80 with some bonuses (USB & bluetooth keyboards, DVI -> VGA adapter.) The machine looks fantastic, and I cannot wait to throw a NUC in it this summer. Unfortunate to hear that the HD5k doesn't want to cooperate, though an Ivy Bridge i5 NUC is significantly cheaper now, since it's last year's tech.

Hopefully, I'll be soon on my way to making a great machine like this. Always have been a big fan, E - can't wait to have my own iMac G4 mod.

-IC

Hi Insane, sounds like you scored a winner! Try as I might, I never got the HD5k to perform perfectly. Your milage may vary, but I can tell you without hesitation that the HD4K works terrific. If you're going to use the same 12/24 step-up converter method that I did, I recommend getting the converter ordered. Mine took FOREVER to get here from China, for both my G4 and G5 20" builds.

Looking fwd to yet another 20" G4 thread, be sure to post lots of photos and your rationale.


Cheers!
 
Hey Ersterhernd,
Any chance you will attempt the HD5K graphics in the 20" iMac now that Chimera has increased support for them and the ULP Haswell CPUs? Looking over which NUC to buy for my mod, and I am wondering if the support in Chimera will help the artifacting.
-IC
 
Hi IC, at this point the 20" is performing so well that I'm going to leave it. "If it ain't broke, don't fix it" is in effect with this one. The grief it caused me was so exhausting that I won't soon forget.

Cheers!
 
You're right ersterhernd, your build and topic are great to read up upon before starting the build. I just gutted the first 20" iMac (was able to buy another 20" for just 40 euro, that's about 52 USD) and ordered the first set of parts and NUC. I'll be reusing the iMacs PSU, but will open a topic to show the progress (I enjoy reading the different mods so lot's of others probably will too). So eager to move on, but this is one of those projects that you'll need to take your time for.
 
Greetings Ersterhernd. I’m in the process of trying to mod a 20” imac G4. I have a couple questions. The extra white wire you mention in post #33, is that tied to the grey cable outer shielding? Both ends of that then go to pico ground and pin 15 of DVI? What about the shielding on the black cable? I’m using HDMI block connector.

I’m had trouble keeping the LCD lit, and now nothing shows up. I’m wondering if I damaged something. Worked great first fire up but backlight would go off. I found the temporary up converter I was using would drop to <18V causing screen to go off, then jump back up to 24V but screen stayed off. I now have the right up converter hoping that would solve it. I now get consistent 24V out keeps the backlight on but nothing shows up on screen.

The wiring error I made. I supplied 5V from pico to red into the 1k resistor. Didn’t realize the red from grey LCD cable was already carrying 5V. I also connected both LCD cable shields together to ground. Both of these instances it lit and got screen boot but would go off cause that temp up converter I was using. Any ideas?
 
Greetings Ersterhernd. I’m in the process of trying to mod a 20” imac G4. I have a couple questions. The extra white wire you mention in post #33, is that tied to the grey cable outer shielding? Both ends of that then go to pico ground and pin 15 of DVI? What about the shielding on the black cable? I’m using HDMI block connector.

I’m had trouble keeping the LCD lit, and now nothing shows up. I’m wondering if I damaged something. Worked great first fire up but backlight would go off. I found the temporary up converter I was using would drop to <18V causing screen to go off, then jump back up to 24V but screen stayed off. I now have the right up converter hoping that would solve it. I now get consistent 24V out keeps the backlight on but nothing shows up on screen.

The wiring error I made. I supplied 5V from pico to red into the 1k resistor. Didn’t realize the red from grey LCD cable was already carrying 5V. I also connected both LCD cable shields together to ground. Both of these instances it lit and got screen boot but would go off cause that temp up converter I was using. Any ideas?


The white wire shown in the photo is a standalone separate one, it goes to ground or pin 17 on HDMI. The shielding can be soldered to a heavy gauge wire and grounded pretty much anywhere. If you're using a block connector to HDMI then pins 18 and 19 can be directly connected via a 1k resistor, its much easier that way. The 5V VEDID then solders to the pin 18 side of the resistor. I don't like the sounds of the your black screen... ouch. Good Luck.

I'm actually in the middle of another A1076 build. Taking my time with it and going well so far. Also want to maybe tackle a 24" model but the 72W required by the backlights makes me shudder.


Cheers
Ersterhernd
 
Thanks Eesterherd. The black screen I found to be a display issue with the G4. Drove me nuts cause it worked perfectly at first, then when I decide its a go to shrink wrap everything, tape and close up the HDMI connector, and connect again no picture. At first I suspects wiring. Backlight was always working. I tore all connections, measure voltages, impedance, rebuilt, and nothing. I had a spare beat up iMac isight G5. Took that screen connected and bang working. The only thing different is the G4 screen has this ribbon cable coming from controller to the side of the panel. The G5 screen doesn't. Also when I shut down it goes to this loop of colors before shutting down. Have you seen this before? Did not do this with the G4 screen when it worked. I'm going to take it apart and have a look at the controller board, maybe its some connector. Otherwise replace the screen.

I'm actually in the middle of another A1076 build. Taking my time with it and going well so far. Also want to maybe tackle a 24" model but the 72W required by the backlights makes me shudder.
Fantastic... Yes I too have a 24" white. I'm thinking replacing that screen with an LED one.
 
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