Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

redheeler

macrumors G3
Oct 17, 2014
8,587
9,184
Colorado, USA
Is it possible to use original iMac power supply somehow with r1811 board?
It may be possible. The original power supply outputs 12v and the R1811 specification says 24v, but 24v is only really needed for USB-C charging. Someone else would have to confirm if the R1811 works with 12v (shouldn't be any danger in trying with a lower voltage).

Edit: For learning about the original iMac power supply, I found this video useful:

Note that he is getting a consistent 12v output from those two pins, so it's very likely that it'd work if the R1811 runs fine on 12v.
 
Last edited:

redheeler

macrumors G3
Oct 17, 2014
8,587
9,184
Colorado, USA
Finally received my r1811 v4.
Connected with my MacBook 14pro on m1pro via type-c. When I turn on HDR 5k display becomes too dim (you can see difference pictures). What’s the problem?
The 5K iMac display doesn't support HDR. Neither does Apple's current Studio Display.
 

PaulD-UK

macrumors 6502a
Oct 23, 2009
870
470
The data sheet for the R1811 lists:
电源输入
Power Input:
待机大电源 DC12V 4A ,5V 3A ,5VSB 1.5A ..... (或者 单 24V 5A)
DC12V 4A ,5V 3A ,5VSB 1.5A ( or single DC24V).
This corresponds to the large white connector on the top of the R1811, next to the red Backlight board connector.
So it looks like this could be a 12v input point.
But maybe all the other two main/StandBy 5v voltage sources would also be necessary?

I don't know if I would take the risk.

Though probably the iMac PSU would prove both 12v and 5v x2.
The above video seems to show the iMac PSU supplies 12v only, and only powers up at reduced SB power until some sort of control voltage/ground is supplied to the small oblique connector strip in the other side of the PCB.
EDIT: Full power is available on post-2012 iMacs with no fiddling with control signals.
R1811-BacklightRedWhitePinout.jpg
 
Last edited:

rusavv

macrumors newbie
Jun 22, 2021
21
45
Do you have the pinouts for LM270QQ1 and LM270QQ2? How do you "reverse" the LCD connector? I am just wondering if I can connect a LM270QQ1 panel to a LG UltraFine 5K board.
Sorry, I don't. I have a handy service man in my area - this guy is literally a magician! He did all the electrical part of the project.
 

rusavv

macrumors newbie
Jun 22, 2021
21
45
About the sensor remote control: I measured the wires mit a multimeter and hoped the cables work like in a traditional remote and are translated. Because I wanted to use the original Power button. Unfortunately it doesn't. So I have to come up with a new plan.
Thunderbolt Display does not have a power key, this solved my problem :)
All I need to do is a custom cable to connect my power board to display's connector.
 

Attachments

  • IMG_4517.jpeg
    IMG_4517.jpeg
    232.5 KB · Views: 122
  • IMG_7018.jpeg
    IMG_7018.jpeg
    499 KB · Views: 124

junna

macrumors newbie
Jan 10, 2024
1
0
Yes I did. The board itself contains an audio amplifier (CSC3110) which can be traced to the four pin header. The volume is more than adequate and can go really loud. I doubt you will set it to anything above 30%.
Since l am not very accustomed to electronics, I dare to venture weather you might have a sketch on the pinout for the wiring pls.
 

ModernMixologist

macrumors newbie
Jan 10, 2024
7
2
Ok... some T18 progress shots... 4 control buttons printed and working in the 4 USB-A slots (plus original power button connected) and other ports blanked, IEC power removed and replaced with a heavy duty DC input, screen taped into place and running up against my iMac Pro. I'll get some internal shots when I next have it open to finish off the extension ports which I am carefully cutting into the original RAM door.

So far so good - its been running all day on my desk for work and is imperceptibly close to the iMac Pro in brightness, colour and accuracy, whilst the panel seems to be running far cooler than the front or back of the iMac Pro (I opted for an external power brick so I can swap input to my caravan when needed).

Might stay this way a week or so before I go digging around in there for the final time though 😆
Sorry to jump back a bit. Researching doing this to my 17,1 Late 2015. Do you have any final external and internal shots of your build? Great job. Would love to hear about your button controls and such. Very neat.
 

ModernMixologist

macrumors newbie
Jan 10, 2024
7
2
The iMac 5K screen panel is only rated 500 nits, so not as bright as the Studio Display.
The boards are designed for the specific internal cabling of the LG iMac panels, which are probably different to the Studio Display Panel.

A recent post here said the T18 was brighter without a Constant Current board than an iMac Pro.
The T18 is very similar to the T19, just different inputs.
Does anyone have a listing of all the I/O on the T19. Can't seem to find those listed anywhere. Just trying to choose which board to get.
 

PaulD-UK

macrumors 6502a
Oct 23, 2009
870
470
The Hajing Cool T19 appears to have two DP 1.4 input ports and two HDMI 2.1 ports.

"Haijing Cool T19 is a multi-function full HD high refresh rate display driver board, supports DSC (Display Stream Compression) function, single DP1.4, HDMI2.1 can transmit lossless 4K 144Hz (12bit) UHD images, HDMI2.1 interface can support PS5 4K 120Hz.
Support HDR high dynamic lighting rendering image output (High-Dynamic Range), which can provide more dynamic range and image details.
The DC input voltage is 24V/12V, the screen voltage can be 5V/10V/12V, with headphone output and two power amplifier outputs within 5 watts (8Ω speakers).
This driver board can complete the HDMI digital signal DP digital signal output from the PC to the control card, and then output the 8LANE EDP HBR2 signal to the TCON module inside the LCD.
It supports DP1.4 digital input interface, and is compatible with HDMI2.1 (VRR) digital input interface and supports HDCP2.2.
This design is mainly used to connect with TFT LCD PANEL, to realize the reproduction of digital input signal with the highest resolution up to 5120*2880@60Hz or 3840*2160@144Hz, and the color up to 1.07 billion pixels.
And has DCR (Dynamic Contrast Adjustment), color enhancement, color engine and other special functions to make the color reproduction more realistic, more vivid and more vivid.
With a variety of OSD interface styles, a variety of OSD languages to choose from."
 

crystalidea

macrumors regular
Apr 3, 2014
188
50
Belgium
u49 with stock settings only allows 4k resolution - no 5k (tried TB3-TB3 Apple cable and DP->USBC cable).

Any ideas? Thanks.
 

Attachments

  • Screen Shot 2024-01-12 at 16.32.56.png
    Screen Shot 2024-01-12 at 16.32.56.png
    448.2 KB · Views: 73
  • Screen Shot 2024-01-12 at 16.31.16.png
    Screen Shot 2024-01-12 at 16.31.16.png
    495 KB · Views: 73

Rembihnutur

macrumors newbie
Jan 12, 2022
19
24
Hey. I got my replacement display today. unfortunately it was completely broken when it arrived.
And it was the wrong one. I ordered a SD B1 and got a SD C1.

Surprisingly, the display itself still worked and what was even more surprising was that the display worked with my board. Since the C1 is the better display compared to the B1, I would of course like to have that instead of the B1. They also cost almost the same.

Can I assume that if one C1 works, another C1 should also work? Are they always the same or are there differences? If I researched correctly, the SD C1 was only installed in the iMac 27 2017.

Can anyone here say anything about it?
 
Last edited:

redheeler

macrumors G3
Oct 17, 2014
8,587
9,184
Colorado, USA
Finally received my R1811, so far I am impressed with it. The backlight seems plenty bright/even and the display quality isn't perceptively different from how I remember it with the original iMac inside. System Information has the charging wattage at 90W and iStat Menus has shown my 16" Intel MacBook Pro drawing more than 60W. Glad I went with the 200W power supply as it will be easily able to handle the load.

Like others have mentioned the fan is loud so I'll look for a solution to that. I also need to mount the board better inside (going to follow @Aiwi's lead on this) and do the speakers. Thanks to everyone who contributed to this thread!
 
  • Like
Reactions: Regulus67 and Aiwi

fhall1

macrumors 68040
Dec 18, 2007
3,875
1,319
(Central) NY State of mind
Getting ready to button up my 27" iMac case and re-install the iFixit adhesive strips. I read earlier in this thread about folks having issues with the glass falling off after a day or so. The advice was to be sure you remove all the old adhesive. So, I spent probably 45 minutes with isopropyl alcohol, cotton swabs, plastic opening tool, and paper towel and got most of the old adhesive off, but there's a strip at the top and bottom of the glass panel, that I've spent an inordinate amount of time with and still they won't come off. I know some folks said to use Goo-Gone, but others said it leaves a residue that can cause the new strips to fail and the glass to fall off.

So - I was wondering what folks here used...or if I use Goo-Gone on those stubborn areas, then clean off any of its' residue with isopropyl - will that be sufficient? My plan is to reinstall the strips, mate the glass to the case, then lay it on its back with blue painter's tape holding the two pieces together for a couple days to let the strips' adhesive set. Then stand it up for a couple days, and then finally remove the painter's tape. Overkill? Am I worrying about this too much?
 

redheeler

macrumors G3
Oct 17, 2014
8,587
9,184
Colorado, USA
Things were going well up until now. I just got some batteries and tried out the included remote...completely non-functional. Changing the backlight brightness was so easy with the Mac function keys, now it is a chore...
 

Imacmonitor

macrumors newbie
Jan 14, 2024
1
0
Just some 3d Printer supports for the r1811 to go in, but monitor works. Didn’t include speakers as use external system also going to leave the psu brink outside. Have a fan control board but the r1811 seems quiet to me in use so not connected. Bought remote control and put ir receiver where the camera was. Love the look and quality
Love your work! Question: did you simply cut up an IR receiver cable and solder it on? Or did you get a 3-pin IR receiver then wired and soldered it? If the later, did you have to use any resistors?

Edit: just realized what you did based on your pictures: unsoldered the IR receiver from the button plate, and just wired it up to where the camera is. I originally thought you got yourself an additional IR receiver to make the connection. Thank you!
 
Last edited:

redheeler

macrumors G3
Oct 17, 2014
8,587
9,184
Colorado, USA
I figured out why my remote wasn’t working. It’s a bad IR sensor. Temporarily connected a different IR sensor and it’s working with that.
 

davidg5678

macrumors regular
Dec 5, 2020
128
108
Things were going well up until now. I just got some batteries and tried out the included remote...completely non-functional. Changing the backlight brightness was so easy with the Mac function keys, now it is a chore...
If you install a program on your Mac called MonitorControl, you can continue adjusting the backlight brightness with the keyboard.
 

jag001

macrumors newbie
Oct 13, 2023
25
27
Sorry to jump back a bit. Researching doing this to my 17,1 Late 2015. Do you have any final external and internal shots of your build? Great job. Would love to hear about your button controls and such. Very neat.
I don't have any final shots as I still have a half done taped up iMac sitting on my desk working beautifully... I'm very good at half doing reno jobs and then using them anyways 😆

Buttons have worked very well and its nice to have them at "easy" reach when setting up the balance against my iMac Pro, I have them 99.5% indistinguishable from each other now.

Will post finished shots soon, hoping to take a bit of time off in the next few days to do the final mods to add input ports to the RAM door and seal it all up finally!
 
  • Like
Reactions: uller6 and PaulD-UK

redheeler

macrumors G3
Oct 17, 2014
8,587
9,184
Colorado, USA
The iMac's design with no vents at the top inhibits cooling, the power supply is getting very hot inside when both the display and connected laptop are drawing max power. I think I will need to get a case fan. Has anyone else added a case fan?
 

PaulD-UK

macrumors 6502a
Oct 23, 2009
870
470
I used a 21" iMac A1418 fan, with proper aluminium duct work to exhaust it out of the original vent.
With PCM temperature control so it runs as inaudibly as in the iMac at low power.

It turns out because I pair it with an M1 mini and don't use USC-C PD power, it only uses less than 50 watts (the internal PSU is 120 watts max) , and nothing gets beyond slightly warm...

04interiorductingfull-jpg.2185043
01interiorfull-jpg.2185035
 
Last edited:

PaulD-UK

macrumors 6502a
Oct 23, 2009
870
470
Just a cheap 4 wire PWM fan controller from eBay, which will work with iMac fans (which are standard PWM but with their + and - wires reversed).
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.