DIY 5k Monitor - success :-)

[Aiwi]

My apologies for the reply almost 2 years after this particular post, but wanted to ask how you cut the perspex for the board mount. I've got some acrylic that I could potentially use, but have had minimal success making holes in it (without cracking) so far. Wondering if 3D printing a mount would be better

I just used drills and a jigsaw. 3d printer would absolutely be better!

 

[bb_mac]

Just received my JRY-W9CUHD-AA1 board - a lot smaller than I expected.

I have a question about future upgrades once I get the board up and running with a 12v power brick.

How to convert the imac PSU cable to connect to the board?

This option requires modification of the iMac PSU output connector wiring to splice adapt it to the power connector on the board.

I've been unable to find any references to how this is done, so I'm assuming it's general electronics and cabling know-how which is required here, rather than anything specific?

Basically to wire from the iMac PSU to a male DC Plug?

Ideally doing so by not cutting into or damaging the 12 pin PSU plug - and choosing the correct pins by referring to a schematic diagram, right?

I can't see how it would be more complicated than that.

EDIT: Found a useful post - there's a wealth of info in this thread, just have to get the search right:

https://forums.macrumors.com/threads/diy-5k-monitor-success.2253100/page-53?post=33075794#post-33075794

I'll keep looking to see if there's a solution to making it all work with the imac power button.

 

[PaulD-UK]

@bb_mac
See this post from @Kaeslin, who did a 'state of the art' build using the iMac's PSU (but with a different board):

https://forums.macrumors.com/threads/diy-5k-monitor-success.2253100/post-33143392

Photo here:

https://forums.macrumors.com/attachments/img_3134-jpeg.2379411/

You need a 5.5mm 5-8 amp barrel plug to connect to the AA1.
If you use a lesser rated (2A) barrel connector it could get very hot.

 

[PaulD-UK]

@Cookbot "I thought I'd save the £3,000 buying..." the cheapest, most basic (in hardware and firmware) conversion boards...

Sorry it hasn't worked out.

12v 5A is only 60 watts, and is at the bottom of the lower limit of a PSU for a 27" 5K monitor.
Test you failing boards and screens with a better spec PSU, because if the one you are using isn't giving the full 60 watts then that could be the cause...

To trouble shoot what is at fault - AA1 or screen panel or cable - you have to test each one systematically.

You have one good AA1, connected with one good cable to one good panel.

So you need to test, and write down the results, of using:

The good AA1 and panel with the other cables.

The good AA1 and the good cable to the other two panels.

The 'bad' AA1s, one at a time, with a good cable to a good panel.

Then report the results here and we may be able to help. 😉

 

[bb_mac]

@bb_mac
See this post from @Kaeslin, who did a 'state of the art' build using the iMac's PSU (but with a different board):

https://forums.macrumors.com/threads/diy-5k-monitor-success.2253100/post-33143392

Photo here:

https://forums.macrumors.com/attachments/img_3134-jpeg.2379411/

You need a 5.5mm 5-8 amp barrel plug to connect to the AA1.
If you use a lesser rated (2A) barrel connector it could get very hot.

Thanks Paul - looks like I'm in luck with a later version of the board, the DC IN is soldered up to a 4 pin header.
Interestingly the HDMI ribbon connector is also present on the board.

 

[ItsAShaunParty]

I bought a Benq monitor, but I think I'm gonna return it. It's not very bright. I'm back, baby!

Updated the makeshift GPT:

ChatGPT - DIY 5K Monitor GPT

A conversational AI system that listens, learns, and challenges

chatgpt.com

For those who don't know, it's an AI bot based on this thread. It's a little weird, but you might find it helpful.

Can someone please make a detailed instructional video? I'm talking speakers, power button, keyboard controls, maybe even a camera, in a 2-hour owc/ifxit style video shot over a few days. You'd get pretty decent viewership. I'd even pay $5 for it. Just saying.

 

[bb_mac]

That's incredibly useful, @ItsAShaunParty ! - nice one. Bookmarked.

Has anyone investigated using the iMac chassis USB port holes with micro-hdmi and micro-dp female adaptors?
Fitting them into those slots? - seriously complicated mounting that so it can take a lot of applied pressure from plugging cables in.

A better idea - a 3D printed part that is non-destructively "mounted" to the back of the imac using the outer two ports on either side and a brace inside the iMac, then cabling is fed into that with the full gamut of connections to match the controller board.

The outside section would be quite chunky - sticking out as much as it needed, with the cables being inserted "vertically" rather than horizontally.

I make it sound so easy ... 😆 - yeah, it's crazy complicated. High skills and lots of time required.

 

[PaulD-UK]

@bb_mac
One major problem has been that no one has managed to find mini or micro HDMI/DP adapters that work at more than 4K resolution.
They are seemingly made for 4K camera systems in drones.

 

[CaliSpain]

Updates on the 2015 iMac 27 "Mystery Mac" with R1811 and DZ-LP0818:

1. DC power barrel jacks: I replaced the 5.5mm/2.1mm barrel jack splitter and adapters with proper 5.5mm/2.5mm barrel jack splitter and adapters. [Source: amazon.es]
2. 24c to 12v buck converter for iMac fan: I installed a selectable buck converter. Output is accurate to its LED display as measured with my multimeter. [Source: amazon.es]
3. Fuse for iMac fan: I added a 5mm x 20mm 2A glass fuse prior to the buck converter. Probably overkill because the buck converter has "overcurrent protection", but anyway... [Source: amazon.es]
4. 180 Ohm resistor for R1811 board fan: Replaced my two Noctua resistors. Measured accurate with multimeter. [Source: aliexpress.com]
5. 3D printed iMac fan duct: I printed @Xarl-li 's Codo_Base_Fan_Imac.stl and Coduc_Int_Fan.stl. I used PLA and have had no warping. [Source: thingverse.com]
6. 3D printed PCB board trays: I created these trays using WJCarpenter's parametric-pcb-base.scad OpenSCAD project at https://gitlab.com/wjcarpenter/3dprinting/-/tree/main/parametric-pcb-base. They are in PLA and haven't warped. I couldn't figure out the kicad coordinate system used, so I used ChatGPT to help me modify the code, changing the coordinates to my "normal" [0,0] in the lower left corner of a board. I'll upload the revised code soon. Haven't had time.
7. Command Strip Picture Hanging Strips: I used these to mount the board trays. Works great, no degradation so far due to heat. Velcro would work, too. [Source: amazon.es]

My next step is to replace the R1811 button PCB with the hardwired original power button, custom control buttons in the USB ports, the LED where the headset jack was, and the IR sensor where the camera was. That's why the 12-pin JST harness is installed. I traced all the signals:

And:

Again, thanks for everyone's help and contributions to this thread!