Ersterhernds iMac G5 20 Inch A1076 Project

[ersterhernd]

Yes, potentiometer will be last resort. Brightness control is the next obstacle. Wow this is been one challenging adventure. Have a look at the attached pic. I found a pin out online. Will that be useful for me if I can tap into pin 35 and 36? I'm confused with this PWM line. Is that that adjustable voltage line?

If you want software controlled brightness, you'll very likely have to implement Kiwi's solution. He and MacTester worked very hard on it and found success. Its possible but unlikely you'll be able to achieve native control from OSX, given that your hardware isn't Apple. That said, there's nothing like trying. Great things are not achieved until great resistance is overcome.

Cheers!

 

[carl]

The iMac PSU is powered on when the red light on the relay is lit up. Relay link here.

Ersterhernd, the wiring on the relay, the red line on the pic goes to "IN" screw and the blacks? I see 2 blacks. I assume they both go to "GND" screw. Where is the 2nd black coming from? On the other side just to make sure you have the black wire on the "COM" screw, and the green wire on the "ON" screw, correct? I have the relay red light on but its not jump starting the PSU. I'm using a 3V one. When I measure input /output, I get 3.2V in and 5.2V out. What am I missing?

 

[ersterhernd]

Ersterhernd, the wiring on the relay, the red line on the pic goes to "IN" screw and the blacks? I see 2 blacks. I assume they both go to "GND" screw. Where is the 2nd black coming from? On the other side just to make sure you have the black wire on the "COM" screw, and the green wire on the "ON" screw, correct? I have the relay red light on but its not jump starting the PSU. I'm using a 3V one. When I measure input /output, I get 3.2V in and 5.2V out. What am I missing?

Those 2 black wires are spliced and go to ground in the NUC (Front Panel pin 5).

 

[carl]

Is the red wire connected to VCC terminal and each of the blacks connected to IN and GND terminals correct?

 

[ersterhernd]

Is the red wire connected to VCC terminal and each of the blacks connected to IN and GND terminals correct?

That's what mine required. Check the spec sheet on your relay to be sure.

 

[carl]

yeah these things don't come with anything. I looked online and nothing. I ordered 2 of them, a 3V and 5V like yours. I'm trying the 3V one cause there where plenty of 3.3V lines to steal from from ribbon connectors. However I think I read the VCC needs 5V. I can get the 3V red light on but either I don't have the connection right or the 3V not cutting it. I'm not sure why. Anyways I went ahead today and got the only 5V closed until powered from another connector. Soldered some leads on it. I'm getting better at soldering little things now, should have done this before screwing up the HDMI connectors. I will try the 5V relay tomorrow. I do have some good news. Remember my thought about pin 35 from LVDS connecter that I found was responsible for brightness control. I tested it today, and by golly I hit the bullseye. When I adjusted brightness in windows voltages matched accordingly. I hope that can translate into actually working when I plug in in the inverter line.

 

[carl]

Hi Ersterhernd. I tried out my HDMI connection through mirroring and it works. However when I try directly with the MB it doesn't display anything. Is this a MB HDMI output issue problem. Did you had to enable in NUC bios or something, or did it work OTB? I'm not sure why it doesn't display. I hope its not bios related or Im screwed.

Anyway small update. That 3.3V relay may have been the issue. The 5V worked perfectly, although not crazy of that loud click it makes. The HDMI terminal block worked great but clearance with back frame which has a protruding section that goes in that slot made it difficult. Didn't recognize it when looking for a home of the block. That area seemed like a nice spot for it.

 

[ersterhernd]

Hi Ersterhernd. I tried out my HDMI connection through mirroring and it works. However when I try directly with the MB it doesn't display anything. Is this a MB HDMI output issue problem. Did you had to enable in NUC bios or something, or did it work OTB? I'm not sure why it doesn't display. I hope its not bios related or Im screwed.

Anyway small update. That 3.3V relay may have been the issue. The 5V worked perfectly, although not crazy of that loud click it makes. The HDMI terminal block worked great but clearance with back frame which has a protruding section that goes in that slot made it difficult. Didn't recognize it when looking for a home of the block. That area seemed like a nice spot for it.

That is very odd. The Intel NUC has a BIOS setting to direct the video signal to either mini DP or mini HDMI. You'll obviously have to get this sorted with OSX as the installed OS, to ensure you get not only the signal but the desired full resolution. Nice work on the terminal block, bang up job! If the signal is clean then thats a major hurdle out of the way.

The click sound of the relay is unfortunately the nature of the beast. The three of these A1076 mods that I completed all use it and have been running for over 18 months now without issue. All are on 10.11.5 El Cap.

Keep going, you're definitely pioneering new ground where no one else has tread.


Cheers!

 

[carl]

I think I've come to a major road block or the end of the road. It looks like a laptop HDMI needs the built in display connected for HDMI out to work. I figured it out how in graphic properties to add/enable a second screen. Then I went ahead and matched the iMac screen res. and applied it as default screen. I figured that should do it. Nothing, once I connected the lcd, bang imac screen came to life, and laptop lcd went dark. It did what I requested default wise but, as soon I disconnected the lcd it reverted to nothing. The only way to continue is if I find a way to trick the LVDS connector, or come from that connector to HDMI, or find some conversion. I hear not easy. If you have ideas please let me know. Thanks as always for the replies.

I think I may open a thread to see if I can get some help.

 

[ersterhernd]

Sorry Carl, differential signalling is something I know little about. I'm not sure if you can somehow 'trick' the system or not. Even if you can, is there a means to recognize the 2nd monitor in OSX or the upcoming macOS?

Watching intently... good luck!