DIY 5k Monitor - success :-)

[PaulD-UK]

@kevinherring There is a possible alternative to the 4K R9513 that has USB-C input and 65W PD output - the R9516.
However StneTaskin only list compatibility with the 2015 21 iMac LM215UH1-SD(A1) screen, not the DS(B1) used in the 2017+ models.

You would need to check this with StoneTaskin, and check the firmware actually does 4096x2304 instead of UHD 3840x2160:

StoneTaskin New 4K R9516 Universal HDR Freesync EDP VBO 144Hz DP1.2 LC

1st. product description R9516 is a LCD monitor driver board that can support UHD. Products support VGA, SVGA, XGA, SXGA, uxga, QHD and UHD resolution TFT LCD screens, such as LG, Philips, Samsung, AUO and other brands of UHD LCD. 2nd. Product Features 2.0 supports hdr10 high dynamic...

stonetaskin.com

Edit: I see you've already noticed s previous post using this board with a 2017 4K iMac:

https://forums.macrumors.com/threads/diy-5k-monitor-success.2253100/page-27?post=32318774#post-32318774

 

[shijan]

Just discovered that DELL U2725QE use same MediaTek MT9801 chip as JRY boards

 

[shijan]

And newest LG 27G850A 4K 240Hz monitor use newest MediaTek MT9810 chip. So i guess future versions of JRY boards may also use this MT9810 chip.

 

[Mowgli10L]

I am just about to embark on this (having done 3 x 27" conversions). I assume your R9513 doesn't have USB-C and thus doesn't support charging the laptop? I am considering using a cable like this that allows you to inject PD charging:

USB C to Displayport 1.4 + Type C Female Power Supply Video Cable 8K@60HZ 2m

Take your DisplayPort further with this video cable. Features: USB-C/Thunderbolt Male to DisplayPort 1.2 Male with USB-C Female for Power Supply Aluminium alloy housing Gold-plated connectors Supports up to 8K@60Hz, 4K@30Hz, 100W Dynamic HDR Tonal enhancer, with HDR support, more vivid colours...

www.innov8wholesale.com

I figure if I use a 19 or 20v PSU with a step-down converter to 12v for the board, I can inject a full 65w into the USB-C line. Any thoughts?

As you say, my R9513 doesnt have USB-c input. There are 2 DP and 2 HDMI ports.

 

[jorycz]

@jorycz
The old R1811 V3 board takes a switched 12V source from the 5 pin PH socket to the left in your picture.
From Right to Left in your pic the voltage is +++–– on each pin.

I don't think the connector is on the correct pins in this stock photo, but I've tested there is switched 12V there.
It's Left to Right +++–– in this picture, and it looks like it's on pins 2 and 3, which are both +ve.
The red and black wires are also reversed...
It's the backlight driver circuit, so not a good idea to take too much power from this socket. 😉

https://stonetaskin.com/cdn/shop/products/DIY-5K-universal-R1811-V-4-Driver-Board-USB-C-Freesync-EDP-DP1-4-Compatible-for_1b68cdfa-99c4-474c-acac-eed0db3da6ed.jpg

That 5 pin PH socket of V4 seems to be the same. 3 pins + and 2 - / GND (clearly marked on the back) and switched so when board goes to sleep, this 12V also go to around 0.4V which is perfect.
Btw with 180 Ohm resistor stock fan is completely silent and today I connected W1209 and attached probe directly to heatsink to eliminate this resistor in case of higher temperature and it works perfectly. Temperature is around 34°C after 30 minutes but it will go higher I think.
I'll do more testing tomorrow, connect similar probe for Noctua PWM fan using this controller and that should be all for this build of first iMac Display.

 

[ricknot]

Does anyone have the pin outs for the small control board for the on screen menu and power switch? I think power is pins 2 and 3 or 2 and 3 from the top of the cable on the 1811 board but want to make sure. If not I can get the multimeter out I guess. Thanks.

 

[PaulD-UK]

@ricknot A pic from earlier in the thread. 😉

 

[ricknot]

Thanks but my board is different. It looks like this.

 

[PaulD-UK]

@ricknot Then you don't have a R1811 board, you have a JRY-W9CUHD-AA1 board.

These are the power switch connections:

It's all listed in this post:

https://forums.macrumors.com/threads/diy-5k-monitor-success.2253100/post-33447926

 

[ricknot]

@ricknot Then you don't have a R1811 board, you have a JRY-W9CUHD-AA1 board.

These are the power switch connections:

View attachment 2516643

It's all listed in this post:

https://forums.macrumors.com/threads/diy-5k-monitor-success.2253100/post-33447926

Yes you are correct! Thanks so much. I am going to connect in the iMac power switch to the cable rather than soldering to the board. Wish me luck.

 

[balika011]

From @SubDriver (24 May 2025)
Converting iMac 5K Retina Display to a Standalone 5K Display

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_____

Video Inputs (Resolution/Hz/bit depth) ​

____

_____

____

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Controller Board	Input Voltage​	HDMI Ports (Protocol)​	DisplayPorts (Protocol)​	USB C (PD Watts)​	Audio Amps​	Driver Chip​	Chip Maker​	USB-A / B Ports (Version)​
R9A18 V1 (Note 4)	12 Vdc​	2 (2.0) (5 (4K/60/8)​	2 (1.2) (5K/60/10)​	None​	10 W​	RTD2718Q​	RealTek​	None​
R9A18 V1.1 (Note 4)	12 Vdc​	2 (2.0) (4K/60/8)​	2 (1.4) (5K/60/10)​	None​	10 W​	RTD2718Q​	RealTek​	None​

The R9A18 V1 uses an RTD2797UPM chip. This is why it needs two dp cables and has external dram.

 

[jorycz]

After the whole day using brightness between 80-90%, heatsink temperature stabilized between 37 and 38 °C depending on the weather, which is currently around 23 °C. I’m curious about hot summer days but I think 180 Ohm resistor will be still OK. I set full cooling when temperature reach 41°C+.

 

[ricknot]

I have my jry-w9cuhd-aa1 up and running and in glorious 5K. I had a hiccup now and then but with the forums help it's working. My only issue is that the daughter board isn't working. I have the iMac power with wired into 1&4 and it turns on and off like a charm. The other switches are not working at all. Menu won't come on. Any ideas?