DIY 5k Monitor - success :-)

[davidg5678]

I guess I just burned my board somehow and I can't turn the monitor on no more.
I misconnected the red/black cables connection like that and plugged the power adapter.

View attachment 2233153

The monitor didn't turn on. I noticed that the power adapter LED light was blinking, and thought I had an issue with my power socket so I tried in two different ones before opening the case and checking for the connections. Now, after connecting it properly, the power adapter LED light keeps blinking. When I unplug the power from the board the LED stays on as it should.


Video of the issue

View attachment 2233154

There was no burning smell or anything... but it doesn't turn on anymore.
Is there anything I could try here? 😩

The blinking LED indicates that there is a short circuit somewhere. The power supply detects the short and prevents itself from turning on so as to protect the electronics. You might have accidentally caused a component to fail in the LED backlight driver circuitry.

Has the driver board ever functioned before the cable was connected backward, or is this your first time operating it? Is it possible that there is another short somewhere else in the iMac, which doesn't necessarily have to do with the misaligned backlight cable?

 

[davidg5678]

Hi All,

There are some awesome looking conversions here.

I have a 2017 iMac with the 5k panel and hoping to make the same mods

Here's my understanding for some of the boards available which will work.

1. R9A18 V1: Only supports DP1.2
2. R9A18 V2: Support DP1.4
3. R1811 V3 + V4: Supports DP1.4 and USB-C.
4. T18: Supports 5k @60HZ (single DP port can support 5K resolution) Type-c port, supporting audio + video + PD 65W reverse charging

Now, I came across another board on Alibaba called the Haijing T19, which claims 5k, with DP 1.4 and more importantly HDMI2.1 and works with the standard iMac LM270QQ1.

https://www.aliexpress.com/i/1005004451833256.html?gatewayAdapt=Msite2Pc

Question: Could this be a newer board and maybe something newer than the current favourite R1811? I'm planning to use this with a Mac Mini M2 Pro or possibly the Mac Studio M2 Max

Areas of concern:

1. Does it have USB-C
2. Can I hook up some speakers

Thanks all.

I think that the main difference between the T18 and T19 is that the T19 lacks USB-C.

Both the T18 and T19 have headphone jacks where you could connect speakers through a separate (and probably inexpensive) amplifier board. I don't think there is a built-in speaker amplifier like the R1811 has, but I cannot tell for sure. I also don't think the T18 or T19 have pin headers for speakers to connect directly (like the R1811).

 

[vakman]

Thanks. Decided to order the R1811 instead from

AU$402.33 10％ Off | DIY 5K universal R1811 V.4 Driver Board USB-C Freesync EDP DP1.4 Compatible for iMac LM270QQ1 LM270QQ2 Screen External Monitor

AU$402.33 10％ Off | DIY 5K universal R1811 V.4 Driver Board USB-C Freesync EDP DP1.4 Compatible for iMac LM270QQ1 LM270QQ2 Screen External Monitor

a.aliexpress.com

Fingers crossed and hope it works well with the Mac Mini Pro M2

Btw, any recommendations for a good PSU to fit within the iMac chassis ?

 

[PaulD-UK]

@vakman Question: Could this be a newer board and maybe something newer than the current favourite R1811?

The Chinese manufacturer of the R9A18/R1811 posted that both the Haijing T18/T19 had the same generation main video chip as the R9A18, and the R1811 has a newer more featured main chip with higher heat rating, hence the fan.
However his whole thread was almost immediately removed.

 

[tcapanema]

I tried everything and even unplugged all cables and put the board out of the iMac chassis but I'm still getting the blinking light. I don't know what happened, but it's really weird.

I just isolated the board from the chassis completely to no avail... I examined all circuits thoroughly and couldn't find anything wrong (I thought that maybe a very small magnetized screw could be stuck in the board, but it's totally clean). Maybe there's something wrong in the connectors, but I really can't tell and I can't turn it on again.

 

[michaelsft]

I've been thinking about just how cheaply I can try this and where I can source the cash to do it from as I don't have a lot of disposable cash right now... and I had a few ideas. The first was to go for a known working iMac that was cheap so slightly older while retaining P3 colour - that's the Late 2015 27" which I picked up for £223 inc postage here in the UK on eBay - a real bargain to be honest simply because the mechanical drive had failed. I just sold the motherboard for £123 after eBay fees and postage so I'm only in for £100 on the iMac chassis and screen - not bad! I was hoping to sell the rest to make up the other £100 but had no takers at all so I've given up. I can take £100 for what I have even if I may have destroyed the screen in the process like an idiot. A new screen would take some time to save up for but maybe I got lucky when it banged against the floor... we'll see!

For the display driver board... I still haven't decided which one I want yet and am keeping a very keen eye on this thread. To fund it I decided to switch banks in the UK here and as part of the switch the new bank will give me £175 which will go most of the way to buying this board. Takes a month for the money to come in but when it does it'll be like getting the board for free - well, that's how I'm looking at it anyway! Apart from the replacement power supply and cable I'll need to buy (and presuming my display is still working OK) I could have this all set up for less than £150 which would be amazing if everything goes according to plan. Imagine getting a 5k monitor for my mac mini with all the quality of the iMac screen for £150 - that would be wild.

It's amazing seeing everyone post their stories on here and genuinely is pretty inspirational for a novice like me. I can't wait to get everything up and running and really enjoy all the success stories and problem solving in this thread. Amazing stuff everyone!

 

[i486dx2-66]

I think that the main difference between the T18 and T19 is that the T19 lacks USB-C.

Both the T18 and T19 have headphone jacks where you could connect speakers through a separate (and probably inexpensive) amplifier board. I don't think there is a built-in speaker amplifier like the R1811 has, but I cannot tell for sure. I also don't think the T18 or T19 have pin headers for speakers to connect directly (like the R1811).

I haven't looked at the T19 specs, but the T18 definitely does have a speaker output - Specifically, it uses the PAM8006A, a Class-D amplifier that puts out 15W per channel.

I did a chip inventory for the T18 in this post:

https://forums.macrumors.com/threads/diy-5k-monitor-success.2253100/post-32187317

 

[yaosiang]

Can someone with M1 Mac and R1811 driver board confirm that they are getting RGB colour format on the OSD menu? I tested the Mac mini M1 with R1811 and although I can get 5K@60Hz, the colour format appears to be YUV (not RGB). Both USB-C and DisplayPort inputs on the R1811 gave the same results. I repeated the tests with the same cables on a Windows 10 Pro laptop and I could get RGB colour format so the issue is definitely not caused by the cables.

On the Mac mini M1:

On the Windows 10 Pro laptop:

I previously carried out chroma subsampling test on the R9A18 in post #283. Results for R1811 as below. It is important that the test is carried out with the UI resolution set to 5120x2880 (scale of 1.0). Otherwise, the test image would look fine even if chroma subsampling is present. I used the test image from RTINGS.

 

[PaulD-UK]

RGB. Same config as you - M1 Mac Mini, R1811, v04 firmware for my D1 screen.
You can see my chroma subsampling screenshot in the first pic (bottom of page) here: #489

 

[yaosiang]

RGB. Same config as you - M1 Mac Mini, R1811, v04 firmware for my D1 screen.
You can see my chroma subsampling screenshot in the first pic (bottom of page) here: #489

View attachment 2235315

Thanks @PaulD-UK.

We have pretty much the same hardware, including the D1 screen so I am not sure why I am not getting RGB colour format. I wonder if it has anything to do with the firmware version. I need to look for a way to update it to V04.

The chroma subsampling test has to be done 1:1 but the OSD menu has confirmed you are on RGB so it's not going to make any difference.

 

[codedj]

Hi all,

My 2014 iMac 5K (SDA2) recently failed (seemingly the logic board—fans would spin blast on boot). I thought I'd open it up and give the monitor conversion a go. I picked up a R1811 board and CableMatters DP-to-USBC cable.

Upon connecting everything to a 2021 16" MBP, I cannot see an image on the display. However:

• My MBP recognizes the display
  • 5K over DP as "G1-27"
  • 4K over HDMI as "RTK H2.1 5K3K"
• The display has a backlight and over DP I can control the intensity of it using MonitorControl
• At no point can I see or access the monitor's OSD menu despite pressing various buttons on the controller

Is there anything I can do or try at this point?
Are all signs indeed pointing to something about the display LCD having an issue?
Or could there possibly be an issue with the board's data cable?

I have enjoyed and very much appreciated reading all of the posts and guidance in this thread so far. Thanks!

Were you able to figure out what the problem was?

I have a Planar IX2790 (https://www.planar.com/media/439284/planar-ix2790-specsheet.pdf). It has worked fine at 5K resolution DisplayPort to DisplayPort single cable for all these years. I recently got a M2 Mac Mini and cannot get the display to work with DisplayPort to USB-C 8K cable. Get a blank screen with back light, OSD doesn't work until I disconnect the cable - same issue as yours. I am able to remote in and see that the mac mini detects it as 5K display @ 60Hz.

The monitor has 2 display ports, 3 hdmi - most pics here have 2 hdmi so probably an older board. Tempted to go for R1811.

Any one has any ideas? Thanks in advance!

Here are the timings using Joevt script:

disp0:

dispext0:
640x480@60.000Hz 0.000kHz 0.00MHz h(16 64 80 -) v(3 4 13 +) (virtual)
800x600@60.000Hz 0.000kHz 0.00MHz h(32 80 112 -) v(3 4 17 +) (virtual)
1024x768@60.000Hz 0.000kHz 0.00MHz h(48 104 152 -) v(3 4 23 +) (virtual)
1280x720@60.000Hz 0.000kHz 0.00MHz h(64 128 192 -) v(3 5 20 +) (virtual)
1280x768@60.000Hz 0.000kHz 0.00MHz h(64 128 192 -) v(3 7 20 +) (virtual)
1280x1024@60.000Hz 0.000kHz 0.00MHz h(80 136 216 -) v(3 7 29 +) (virtual)
1400x1050@60.000Hz 0.000kHz 0.00MHz h(88 144 232 -) v(3 4 32 +) (virtual)
1680x1050@60.000Hz 0.000kHz 0.00MHz h(104 176 280 -) v(3 6 30 +) (virtual)
1600x1200@60.000Hz 0.000kHz 0.00MHz h(112 168 280 -) v(3 4 38 +) (virtual)
1920x1080@60.000Hz 0.000kHz 0.00MHz h(128 200 328 -) v(3 5 32 +) (virtual)
1920x1200@60.000Hz 0.000kHz 0.00MHz h(136 200 336 -) v(3 6 36 +) (virtual)
2048x1536@60.000Hz 0.000kHz 0.00MHz h(152 224 376 -) v(3 4 49 +) (virtual)
2560x1440@60.000Hz 0.000kHz 0.00MHz h(192 272 464 -) v(3 5 45 +) (virtual)
2560x1600@60.000Hz 0.000kHz 0.00MHz h(192 280 472 -) v(3 6 49 +) (virtual)
3840x2160@60.000Hz 0.000kHz 0.00MHz h(312 424 736 -) v(3 5 69 +) (virtual)
4096x2160@60.000Hz 0.000kHz 0.00MHz h(8 32 40 +) v(48 8 6 -) (virtual)
5120x2160@60.000Hz 0.000kHz 0.00MHz h(8 32 40 +) v(48 8 6 -) (virtual)
5120x2880@60.000Hz 0.000kHz 0.00MHz h(48 32 80 +) v(3 5 74 -) (virtual)
800x600@60.000Hz 0.000kHz 0.00MHz h(40 128 88 +) v(1 4 23 +) (preferred)
800x600@56.000Hz 0.000kHz 0.00MHz h(24 72 128 +) v(1 2 22 +)
640x480@75.000Hz 0.000kHz 0.00MHz h(16 64 120 -) v(1 3 16 -)
640x480@72.000Hz 0.000kHz 0.00MHz h(24 40 128 -) v(9 3 28 -)
640x480@60.000Hz 31.500kHz 25.20MHz h(16 96 48 -) v(10 2 33 -)
1280x1024@75.000Hz 0.000kHz 0.00MHz h(16 144 248 +) v(1 3 38 +)
1024x768@75.000Hz 0.000kHz 0.00MHz h(16 96 176 +) v(1 3 28 +)
1024x768@70.000Hz 0.000kHz 0.00MHz h(24 136 144 -) v(3 6 29 -)
1024x768@60.000Hz 0.000kHz 0.00MHz h(24 136 160 -) v(3 6 29 -)
800x600@75.000Hz 0.000kHz 0.00MHz h(16 80 160 +) v(1 3 21 +)
800x600@72.000Hz 0.000kHz 0.00MHz h(56 120 64 +) v(37 6 23 +)
2048x1152@60.000Hz 0.000kHz 0.00MHz h(26 80 96 +) v(1 3 44 +)
1920x1200@60.000Hz 0.000kHz 0.00MHz h(136 200 336 -) v(3 6 36 +)
1920x1080@60.000Hz 67.500kHz 148.50MHz h(88 44 148 +) v(4 5 36 +) (preferred)
1680x1050@60.000Hz 0.000kHz 0.00MHz h(104 176 280 -) v(3 6 30 +)
1600x1200@60.000Hz 0.000kHz 0.00MHz h(64 192 304 +) v(1 3 46 +)
1600x900@60.000Hz 0.000kHz 0.00MHz h(24 80 96 +) v(1 3 96 +)
1280x1024@60.000Hz 0.000kHz 0.00MHz h(48 112 248 +) v(1 3 38 +)
1280x800@60.000Hz 0.000kHz 0.00MHz h(72 128 200 -) v(3 6 22 +)
3840x2160@60.000Hz 135.000kHz 594.00MHz h(176 88 296 +) v(8 10 72 +) (preferred) (promoted)
2560x1440@59.951Hz 88.787kHz 241.50MHz h(48 32 80 +) v(3 5 33 -)
1920x1080@59.940Hz 67.433kHz 148.35MHz h(88 44 148 +) v(4 5 36 +) (preferred)
1920x1080@50.000Hz 56.250kHz 148.50MHz h(528 44 148 +) v(4 5 36 +) (promoted)
1280x720@59.940Hz 44.955kHz 74.18MHz h(110 40 220 +) v(5 5 20 +) (promoted)
1280x720@60.000Hz 45.000kHz 74.25MHz h(110 40 220 +) v(5 5 20 +) (promoted)
720x480@59.940Hz 31.469kHz 27.00MHz h(16 62 60 -) v(9 6 30 -) (promoted)
720x480@60.000Hz 31.500kHz 27.03MHz h(16 62 60 -) v(9 6 30 -) (promoted)
720x576@50.000Hz 31.250kHz 27.00MHz h(12 64 68 -) v(5 5 39 -)
640x480@59.940Hz 31.469kHz 25.17MHz h(16 96 48 -) v(10 2 33 -)
3840x2160@59.940Hz 134.865kHz 593.41MHz h(176 88 296 +) v(8 10 72 +) (promoted)
3840x2160@29.970Hz 67.433kHz 296.70MHz h(176 88 296 +) v(8 10 72 +) (promoted)
3840x2160@30.000Hz 67.500kHz 297.00MHz h(176 88 296 +) v(8 10 72 +) (promoted)
3840x2160@25.000Hz 56.250kHz 297.00MHz h(1056 88 296 +) v(8 10 72 +) (promoted)
3840x2160@23.976Hz 53.946kHz 296.70MHz h(1276 88 296 +) v(8 10 72 +) (promoted)
3840x2160@24.000Hz 54.000kHz 297.00MHz h(1276 88 296 +) v(8 10 72 +) (promoted)
1920x2160@60.000Hz 135.000kHz 297.00MHz h(88 44 148 +) v(8 10 72 +)
2560x2880@59.982Hz 177.665kHz 483.25MHz h(48 32 80 +) v(3 10 69 -)
-> 5120x2880@59.980Hz 176.462kHz 967.01MHz h(24 96 240 +) v(48 8 6 -) (preferred)

 

[Stable Entropy]

Were you able to figure out what the problem was?

Unfortunately not. I was able to get a new video data cable and that did not work, so the issue is either with the board itself or the screen. Per suggestion of another poster, my feeling is that there is a board firmware incompatibility with the specific revision of my screen.

I'm trying to figure out what options I have with this R1811 board that I have which may or may not be problematic. Best would be able to get a return, but not fully optimistic there and not quite ready to offer up for free just yet.

I think my DIY journey ends here, but it was still good to open up the machine to pull the drives out. Will still be monitoring the thread to see the fun builds that pop up.

 

[PaulD-UK]

@CaptainAndrew ...my feeling is that there is a board firmware incompatibility...

WRT R1811 firmware versions.
There are various discussions earlier in this thread about updating the R1811's firmware with a Windows PC.
However in post #331 in Aug 2022 the Chinese manufacturer/supplier of this board was quoted as follows:

StoneTaskin said:
R1811 ...The latest version of firmware ...StoneTaskin-01 StoneTaskin-02 and StoneTaskin-03,
Feel free to send me the email address and I will send you the latest version of it.

His posts to this thread no longer exist as it seems they were immediately deleted, but he has a company website and sells on AliExpress.
This is the R1811 Firmware page:

DIY 5K universal R1811 V.4 Driver Board USB-C Freesync EDP DP1.4 Comp

For creating a good consumer experience, please confirm your LCD/LED Screen part number before ordering. If you're a wholesale/distributor in your country please contact us for a better price and the best logistic options...

stonetaskin.com

 

[chocolaterabbit]

I bought my R1811 from this vendor - excellent service and delivery from them.
They flashed the board's firmware to be appropriate for my D1 LCD panel.

Is the only difference between R1811 versions for each panel revision the firmware and can you flash it yourself? I ask as I am trying to get 2 broken imacs, a 2015 and a 2019 which I believe is revision SDB and SDE respectively but I'm not sure if either screen would work. If it's just a firmware update then it'll be possible to switch testing between the 2.

 

[PaulD-UK]

You need to ask a vendor for detailed info about the need for different firmware versions for different panels.
It may be that its different cabling to the panel that is needed rather than the firmware?

Posts #40-48 of this thread describe the firmware update process:

Posted by @runtime_error0x​

"...the seller gave it to me, just had to ask if there was a different image with the dual DP input.

They give you the program to use (only on Windows) and the image to flash, then you just select a couple stuff and hit the flash button. Pretty painless but bit scary since one wrong move could brick it.

The update is done directly through DisplayPort. Yes the single DisplayPort is still at 1.4. You don't really have to pull it out as long as the a DisplayPort connection is accessible to connect to a Windows machine."

 

[yaosiang]

Is the only difference between R1811 versions for each panel revision the firmware and can you flash it yourself? I ask as I am trying to get 2 broken imacs, a 2015 and a 2019 which I believe is revision SDB and SDE respectively but I'm not sure if either screen would work. If it's just a firmware update then it'll be possible to switch testing between the 2.

I believe there is a firmware for each LCD panel (LM270QQ1, LM270QQ2, etc.). The firmware for each LCD panel should work for all revisions (for e.g. SDB1, SDC1, SDD1, etc.).

When you purchase the driver board from AliExpress, you are required to select the LCD panel but not the revision. The seller will also supply the backlight cable according to the LCD panel specified as they are all different.

I have tested the R1811 with at least 2 panels (D1 and E1) and the R9A18 with 4 panels (A3, B1, D1, E1). They all work without any issues.

 

[xMarty]

Hi,

I'm a new member and follow this thread for a few weeks, reading everything up and down. I'm still unsure which driver board I should get since T18 and T19 are not available anymore to ship to my country.

I have an iMac 27" 5K panel LM270QQ1 SD C1, and I researched different driver boards on AliExpress to find differences I can not explain. Maybe someone could shed some light on this.

1. Initially I planned to buy T18/T19, but have to switch plans to buy an R1811 board. I came across these two boards, which claim both to be R1811 but with differently designed boards and huge differences in price:

R1811 with a fan and €290 price tag: https://www.aliexpress.com/item/1005002506761346.html
R1811 without a fan and a €160 price tag: https://www.aliexpress.com/item/1005002506730455.html

I can not tell why there is such a price difference.

2. Then I researched these two R9A18 boards, with a difference in price.
Interestingly, the cheaper board for €170 only asks for the model of the panel. For the more expensive board, the exact revision of the panel must be specified when ordering. But they seem to be the same boards.

Board not asking for revision for €172: https://www.aliexpress.com/item/32965911057.html
Board asking for revision for €213: https://www.aliexpress.com/item/1005004077468105.html

I have read in recent posts that with the correct choice of panel type, the boards should work regardless of revision. Why does this vendor make a difference and require the revision to be selected?

I am really unsure which board to buy. The choice was R1811, as these boards are the latest generation and support DP 1.4 with DSC. According to this website https://khronokernel.github.io/macos/2022/03/01/5K-MONITOR.html, R9A18 boards should only support DP 1.2 and need two DP cables. However, the two R9A18 boards linked above are capable of DP1.4 and support the connection via one DP cable. Is there a newer version of the R9A18 boards with DP 1.4?

Thanks for reading. Maybe this helps others decide, and maybe someone can fill in the gaps of knowledge I have to make a good buying decision and understand more about the boards.

Thanks.

 

[priva28]

Hey @PaulD-UK, I'm really interested in hearing more about how you got the fan working in your setup. Do you have any more info on what PWM fan controller and temp sensor you used to get it working with the iMac fan. Were you able to just wire it up directly to the iMac fan or did you have to do something else?

Also, in regards to getting the speakers working, do you think I'll be fine with these components just wired in series to the woofer and tweeter connections?

AC20-15 0.15mH 20 AWG Air Core Inductor Coil - Dayton Audio

AC20-15 0.15mH 20 AWG Air Core Inductor Coil - Dayton Audio - Dayton Audio 20 gauge air core inductors are a great choice and the best value for building high quality crossovers. Features fully annealed refined copper wire, perfect layer windings and air core construction to ensure no hysteresis...

www.theloudspeakerkit.com

DMPC-10 10uF 250V Polypropylene Capacitor - Dayton Audio

DMPC-10 10uF 250V Polypropylene Capacitor - Dayton Audio - Make the Dayton Audio line of metallized polypropylene capacitors your standard choice for all of your loudspeaker projects! The same high quality as the competing brands... but at a much lower price. They are suitable for a wide range...

www.theloudspeakerkit.com

 

[PaulD-UK]

Hi, looking at the three controllers, left to right:
L Jcf2404 2 wire fan controller for the R1811's heatsink fan. Temp sensor clipped to R1811 heatsink. Set to F(ixed) speed control - off below 30ºC, max >50ºC.
C CN4015-3 DC to DC convertor. Fed 24v from main PSU. Output 10v to the two fan controllers either side.
R 50K3950 v2 (or ZFC39 v2) PWM 4 wire fan controller. Temp sensor extended with copper wires to PSU.
Fan 1 Output 4 wires to A4018 iMac fan. Dip switches set to give lowest 20% speed below 40ºC sensor temp,
max >55ºC.

The iMac fans have their wiring slightly different to PC 4 wire fans. The +ve and GND (-ve) wires are swapped.
So looking at the back of the fan where the wires emerge from the motor hub, the connections are (L to R):
+ve -ve Speed PWM. On the 50K3950 the connections are - + S PWM.

Dayton Audio products are excellent. Better quality than needed...
Those both look good and will work well.
I couldn't fit air cored inductors as I didn't have room, so I wound some round ferrite cores using a cheap
LCR-T4 tester to get the inductance right.

One point to watch - if you clip a temp sensor to the R1811's heatsink, take care as it is spring loaded and easily moved, which could damage the thermal paste under the heatsink.
Have fun!

 

[PaulD-UK]

@xMarty
1.
"R1811 with a fan and €290 price tag::"
This is a R1811 sold by a seller who deals with western buyers.

"R1811 without a fan and a €160 price tag::"
The picture is a completely different 5K 8-bit board: Jiarunyuan 4k 5K driver board type-c JRY-W9CUHD-AA1.
See post #556 of thus thread.
2.
"Board not asking for revision for €172"
This seller regularly deals with the west, and wants to be competitive in price, and can communicate in English ( or other Western languages) and so get the details of the order sorted by email.

"Board asking for revision for €213"
This is an unknown seller to me, and is probably trying to get a higher price.

The R9A18 and R1811 boards are from the same designer/manufacturer.
Revision V1 boards are R9A18 DP 1.2 - 5K 10-bit with 2 DP cables.
V2 boards (or maybe V1.1) are R9A18 DP 1.4 - 5K 10-bit with 2 DP cables or 8-bit with 1 DP cable
V3 boards are R1811 DP1.4 with no dedicated 12v fan socket - 5K 10-bit with 1 USB-C or DP cable (with DSC).
V4 boards are R1811 DP1.4 with final circuit revisions - 5K 10-bit with 1 USB-C or DP cable (with DSC).

To get 5K 10-bit from non-DSC (display stream compression) graphics cards, the firmware of the R1811 has to be flashed to use the 2 DP 1.2 mode. (I think the alternative firmware still retains DP1.4 compatibility.)

I think if you buy a new R9A18 board from China now it will be DP1.4, capable of running 5K via a single (8K compatible) USB-C>DP cable. I'm not sure if its 8 or 10-bit?
See Luke Miani's video in this post #182.

However as mentioned in post #688, the R1811 is supposed to be a better version than earlier boards. FWIW.

"T18 and T19 are not available anymore to ship to my country."
Like Luke Miani, I chose to buy from a (Chinese) eBay seller, to avoid difficulties of dealing direct with AliExpress, YMMV.

 

[priva28]

The iMac fans have their wiring slightly different to PC 4 wire fans. The +ve and GND (-ve) wires are swapped.
So looking at the back of the fan where the wires emerge from the motor hub, the connections are (L to R):
+ve -ve Speed PWM. On the 50K3950 the connections are - + S PWM.

Dayton Audio products are excellent. Better quality than needed...
Those both look good and will work well.

Have fun!

Thanks so much for the info! I ended up playing around with it today and was able to get the fan working using an old Arduino Nano and buck converter I had laying around. Suuuuper jank, but it works!! 😄 Just need to get a temp sensor, write a sketch, and package this up properly then I should be able to use it. Will try to design and 3D print a exhaust for the fan too.

I'm powering the fan with the 12V from the R9A18 power supply, and using the buck converter for 5v to the Arduino.

Today I also added a USB extender to one of the port holes, and an ethernet connection so I always have a hardwired network connection to my MacBook when I connect!



Also ordered those components for the crossovers for the speakers which will be fun to get working. After that, I can package it all up.

Ahh I'm excited.

 

[priva28]

The only issue remaining with my setup is that brightness control seems to be broken on my R9A18 . It seems to be stuck at something around 50-100%. Bc I bought the board so long ago, I can't get a replacement and the seller said the only option would be to send it back for them to look at which might take a few weeks + I have to cover shipping costs back to China which will mean it's probably not worth it since everything else works perfectly fine.

If anyone else has any ideas on how to fix this, or where on the board I should diagnose to understand what is going wrong, I'd really appreciate it!

 

[3quid]

Hi All,

There are some awesome looking conversions here.

I have a 2017 iMac with the 5k panel and hoping to make the same mods

Here's my understanding for some of the boards available which will work.

1. R9A18 V1: Only supports DP1.2
2. R9A18 V2: Support DP1.4
3. R1811 V3 + V4: Supports DP1.4 and USB-C.
4. T18: Supports 5k @60HZ (single DP port can support 5K resolution) Type-c port, supporting audio + video + PD 65W reverse charging

Now, I came across another board on Alibaba called the Haijing T19, which claims 5k, with DP 1.4 and more importantly HDMI2.1 and works with the standard iMac LM270QQ1.

https://www.aliexpress.com/i/1005004451833256.html?gatewayAdapt=Msite2Pc

Question: Could this be a newer board and maybe something newer than the current favourite R1811? I'm planning to use this with a Mac Mini M2 Pro or possibly the Mac Studio M2 Max

Areas of concern:

1. Does it have USB-C
2. Can I hook up some speakers

Thanks all.

Hi,

I’m in a similar spot as you.

I currently have a late 2014 27” 5k iMac - I’ve opened the machine and the panel is an LM280QQ1 (SD)(A3). I’m about to buy a Mac mini M2. I’d like to get these to work together nicely, preferably only using a single port from the mini. I don’t think I’m all that fussed about 8/10bit unless someone can tell me a reason I should be?

The T19 board you posted looks good. Cheaper than the R1811. Have you bought that now? If not, which board did you opt for?

I’ve read this whole thread but still a bit unsure of the simplest way to achieve a good result.

I’d also like to make use of the speakers if possible but I’m not an electronics guru so anything to technical and I’ll just accept I can’t and Bluetooth to something.

Any advice welcome.

 

[davidg5678]

Hi,

I’m in a similar spot as you.

I currently have a late 2014 27” 5k iMac - I’ve opened the machine and the panel is an LM280QQ1 (SD)(A3). I’m about to buy a Mac mini M2. I’d like to get these to work together nicely, preferably only using a single port from the mini. I don’t think I’m all that fussed about 8/10bit unless someone can tell me a reason I should be?

The T19 board you posted looks good. Cheaper than the R1811. Have you bought that now? If not, which board did you opt for?

I’ve read this whole thread but still a bit unsure of the simplest way to achieve a good result.

I’d also like to make use of the speakers if possible but I’m not an electronics guru so anything to technical and I’ll just accept I can’t and Bluetooth to something.

Any advice welcome.

I have been very satisfied with the T18 board I installed in my 2014 5K iMac about a month ago. I had the R1811 installed before, but I actually found I prefer the T18 board as it is both cheaper and less glitchy.

You can connect the T18 to your Mac Mini with a single DisplayPort 1.4 to USB-C cable.

I wouldn't personally worry about the 8-bit vs 10-bit color debate. While it hasn't been verified whether or not the T18 is 10-bit, I can vouch that it looks absolutely fantastic, no different than the original iMac logic board or the R1811.

If you are after the simplest approach, I would recommend that you skip reusing the internal speakers. These will require additional electronics tinkering, and will never sound exactly the same as before the mod. As long as you have room on your desk (and don't mind the look), some decent wired external speakers plugged into your Mac Mini will sound better and be much easier to set up.

At least for simplicity's sake, my advice is to cram as little as possible into the iMac chassis. Just stick with the T18 board alone, and don't put anything else inside. This way, you will have plenty of room to mount the board and route wires with the least amount of tinkering required. There's no need to wire up the original power button or power plug unless you want to. You can snake the T18 buttons and wires out of the iMac's RAM hatch.

Regarding the T18 vs T19: I am not aware of anyone who has tested out the T19 yet on this thread. It is probably fine, but there is a lack of information. If you scroll back the last several pages, however, there have been several successes with the T18.

 

[3quid]

I have been very satisfied with the T18 board I installed in my 2014 5K iMac about a month ago. I had the R1811 installed before, but I actually found I prefer the T18 board as it is both cheaper and less glitchy.

You can connect the T18 to your Mac Mini with a single DisplayPort 1.4 to USB-C cable.

I wouldn't personally worry about the 8-bit vs 10-bit color debate. While it hasn't been verified whether or not the T18 is 10-bit, I can vouch that it looks absolutely fantastic, no different than the original iMac logic board or the R1811.

If you are after the simplest approach, I would recommend that you skip reusing the internal speakers. These will require additional electronics tinkering, and will never sound exactly the same as before the mod. As long as you have room on your desk (and don't mind the look), some decent wired external speakers plugged into your Mac Mini will sound better and be much easier to set up.

At least for simplicity's sake, my advice is to cram as little as possible into the iMac chassis. Just stick with the T18 board alone, and don't put anything else inside. This way, you will have plenty of room to mount the board and route wires with the least amount of tinkering required. There's no need to wire up the original power button or power plug unless you want to. You can snake the T18 buttons and wires out of the iMac's RAM hatch.

Regarding the T18 vs T19: I am not aware of anyone who has tested out the T19 yet on this thread. It is probably fine, but there is a lack of information. If you scroll back the last several pages, however, there have been several successes with the T18.

Thanks David. That is amazing advice.

Can you by any chance post a link to the board you used? Did you get it from eBay or Ali express?

Is this the board we’re looking for? 🤖

5K driver board motherboard HDR DP1.4 Type-C Freesync For driver iMac 27 '' A1419 A2115 5K LCD LM270QQ1 LM270QQ2

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