DIY 5k Monitor - success :-)

[PaulD-UK]

@ItsAShaunParty
Haha, that shows the good, the bad, and hints at the ugly in AI... 😉
All wrapped up in non-technical language that gives everything equal weight, so doesn't help decision making.
Definitely worth doing (👍) but the sampled data-pool needs more critical assessment (which doesn't happen in a thread like this).

"I think I need to be realistic with myself —"
There's a lot to sort out when planning a conversion, and it's a good thing to keep the overall plan simple.

 

[drlamb]

First power up sans-speakers was a success! I did not order the HDMI 2.1 (using DP anyways) version from StoneTaskin but can confirm my board came with seemingly updated firmware (I don't see any of the typos mentioned previously etc.). My R1811 has a build date of 09/2025.

One thing came up as I started to wire up the speakers. Which variant of the YLY-2088 would you use and why?


Edit: Removed duplicate pictures already present in thread. See Paul's comments/links below explaining the difference between the two.

 

[PaulD-UK]

@drlamb
The Mk2 version is (for iMac use) electronically identical to the original one with ABCD jumper settings.
The values are optimal for 8 ohm speakers, so would work best in an iMac with two pairs of speakers in series... 😉

The blue bass-boost capacitor looks to be 22 microfarad in Mk2, but it is 100 microfarad in Mk1.
It is ONLY NEEDED when you are using the crossover with an additional subwoofer circuit (like in a car)... 😵‍💫

To match the Mk 1 version, the #4 is identical to the Mk1 version with jumpers A,B,C and D connected.
This just uses the Tweeter capacitors, but removes the inductor (and the blue bass-boost capacitor) from the circuit.

Removing jumper B in Mk1 inserts the inductor, but with iMac 4 ohm speakers that may cut the midrange response.
To match that with Mk2 use this:

#5 or #6 cannot be matched with the Mk1 version.

Edit: Here's a quick doodle of the circuit:

 

[DavArm]

I installed the a1419 display in the a1312 case. The difference is 1.5 mm, you need to extend it and the display will fit perfectly, and you can use magnets to have constant access to the insides.

Hi, I have an a1419 LCD for which I have acquired a conversion kit for. I purchased the lcd only (Not the LG LCD, rather, the imac lcd itself with all of apple's added frames and what-nots).
I was trying to figure out a way to either mount it on a custom backplate or some alternative chassis and stumbled upon this thread.

I was wondering if you could share a bit more detail about the process and about how you managed to fit the screen in the a1312 case? how is it held in place? did you use glue of any sort?
Any other pictures to show the build a bit more in detail other than the ones you shared?

Do you (or anyone else for that matter) happen to know the dimensions of the screws on the sides and the bottom (underneath the tape) of the imac's backside?

Thanks in advance, and best regards.

 

[PaulD-UK]

@DavArm "...how you managed to fit the screen in the a1312 case? how is it held in place? did you use glue of any sort?"
@gul1ver says he used magnets.
@Borzab used the original iMac adhesive strips, stuck to plywood strips behind the screen glass borders.

"Do you (or anyone else for that matter) happen to know the dimensions of the screws on the sides and the bottom (underneath the tape) of the imac's backside?"

Sorry, that's not clear.
Which iMac? Or do you mean an A1419 iMac's screen panel?

 

[DavArm]

Thanks @PaulD-UK for your reply.

I indeed meant the A1419's 27" 5k screen panel. Specifically the - LM270QQ1-SDB2.

I am mostly interested in knowing how does the panel rest inside the a1312's case? The original panel of the a1312's iMac had a frame with magnets that held it in place, but that frame ( I assume) cannot be mounted on the a1419's panel.
I prefer the panel to be in a case over using adhesive strips. I just don't trust It holding the panels weight (and I also want to mount it on an adjustable arm later on).

I was wondering if @gul1ver 'd happen to have more-detailed pictures they could share of the transplant or any tips about the process they went through getting the panel to stay still inside the case? ( Just to be clear and not come-off as an ****** : I'm not expecting you to tear anything down, of course)
Also, did you use the LG model for the conversion, or did you use an iMac panel?

Any bit of information \ suggestions for a case would be of great help and would be very much appreciated🙏
I'd really like to finally put this beautiful display to use.

Thanks in advance, and best regards.

 

[VegetarianNachos]

Need advice and cable recommendations!

I would like to use the two DisplayPort inputs and the usb-c input on my (yet to arrive) R1811 v4 and need some advice. I was thinking of using 1.5-2' extensions for each of the ports and have the extensions coming out of a modified ram door. I would like to use a usb-c to DisplayPort cable to connect to each of the DisplayPort extensions for use with different Macs as necessary. I would also like to use a usb-c to usb-c cable to connect to the usb-c extension as necessary. It would need to be able to power the display as well as provide charging to a MacBook.

My questions are:

1. Is 1.5-2' long enough for extension cables, or should I use longer ones?
2. What total cable lengths for each controller board port do I need to stay under in order to maintain 5k/60/10 video? I was planning to get 3.3' cables or possibly one 6' cable to be used for the main display cables (which would be added to the 1.5-2' extension cables for total lengths of 5.3' to 8'.
3. Is there a specific type of cable that is DisplayPort to DisplayPort I would need to use if I were to use the display with a PC?
4. I am not planning to use the HDMI ports. Should I still use 1-2 HDMI extension cables through the ram door (for a reason I have not thought of yet)?
5. Does anyone have recommendations on cable brands/types that I should consider for this build?
6. If I use the 5a power supply that comes with the R1811 (from StoneTaskin), can I still use the usb-c port to charge a MacBook Pro? (will it just draw available power, and charge slower?).

 

[erihp]

My preferences snd answers are by no means gospel here <bows to PaulD UK, they holiest>, but my two cents:

1) I would use cables that are a short as possible. This will give you breathing room on the cable you use from the source side.

2) Depends greatly on the quality of the cables. Dont cheap out.

3) Displayport to Displayport cables do exist. Again dont cheap out, may as well get a 2.1-spec cable.

4) Yes

5) Look for certifications and data from tests if possible.

6) Maybe - Defer to someone who has used this board/PSU, I have not.

 

[PaulD-UK]

@VegetarianNachos
Using a 24V 5A PSU with a R1811 to power a MBP would only provide 60W at best.
A higher rated PSU could allow higher charging rates.
The PSU would need to be rated to give 100% power for extended periods.

I think the PSUs StoneTaskin supply are probably capable of this, but it remains to be tested in actual use.
Buying a certified PSU, with a data sheet showing how its performance varies under stress or heat, and its MTBF rating, could give a better outcome.

The USB standard does NOT support extension cables.
The reason for this is that to use USB PD charging for a laptop, the cable should have an ID chip embedded in it to identify its safe charging rating.
If you add an extension then this won't have the ID chip, and the extension's rating for safe charging cannot be determined.

In practice, if you make sure the extension comes with packaging displaying a suitable power rating, then this usually isn't a problem...

When buying cables (or extension cables) the important thing it to make sure that the cable is rated for 8K video.
Most cheaper cables are only rated for 4K/60Hz video, and usually these fail when used with a 5K monitor.

Using an (8K) USB-C to DP 1.4 adapter cable works very well.
I've used Cable Matters cables, but any good brand will be fine.

With HDMI it is even more important to get a HDMI 2.1 cable for 5K, because HDMI 2.0 can only manage 4K.
You need a R1811 HDMI 2.1 board for this.

Because the R1811 isn't a Thunderbolt 3 board, it is more tolerant of the cables that work, so in practice, cable length, or extension or adapters isn't a problem.
But the less, length or extensions/adapters, the better.

 

[VegetarianNachos]

I now have my R1811 v4 board and have it hooked up and working. Connecting the backlight cable was hard, it was a very tight fit.

What software should I use to fully check out the display to make sure it is at 5k/60/10?

How do I check the board firmware and know that it is the latest version?

Is there a wiring diagram for the crossover boards?

 

[PaulD-UK]

@VegetarianNachos "2. What software should I use to fully check out the display to make sure it is at 5k/60/10?"

What version of firmware are you running?
If the OSD is bright blue and yellow then there is a Factory option on the second page of the OSD options that displays this data.

If your OSD is cyan coloured and says V04 (at the top right of the OSD) then, except for the resolution, this information isn't displayed in the OSD, and you have to analyse test images on the monitor screen to determine the node of operation.
Look at How to Test for Chroma Sub-sampling on this page.

You need to download the test image, and open it in preview at 100% size.
The screen should be set to 5K res, not HiDPI, so 5120x2880;
The image is really small at the correct 100% size.

Then take an iPhone photograph to record the look of the image.
If it is not clear then you are not getting full colour information.

 

[VegetarianNachos]

@VegetarianNachos "2. What software should I use to fully check out the display to make sure it is at 5k/60/10?"

What version of firmware are you running?
If the OSD is bright blue and yellow then there is a Factory option on the second page of the OSD options that displays this data.

View attachment 2568621

If your OSD is cyan coloured and says V04 (at the top right of the OSD) then, except for the resolution, this information isn't displayed in the OSD, and you have to analyse test images on the monitor screen to determine the node of operation.
Look at How to Test for Chroma Sub-sampling on this page.

View attachment 2568622

Well that is a bummer. I have the cyan V04 version of firmware. Brightness keys are not working from the keyboard, and I did buy the board directly from StoneTaskin.

 

[PaulD-UK]

@VegetarianNachos You need to download Better Display (from GitHub, the free version is enough) to get keyboard control.
It's called DDC/CI and BD has an auto-configure tab to get it working.

BD also allows you to set different colour modes, which helps to test what you are getting on-screen.

 

[VegetarianNachos]

@VegetarianNachos You need to download Better Display (from GitHub, the free version is enough) to get keyboard control.
It's called DDC/CI and BD has an auto-configure tab to get it working.

BD also allows you to set different colour modes, which helps to test what you are getting on-screen.

Looks like it is working at 5k/60/10 okay. Now I just need to figure out how to attach the crossover boards. Thanks!

 

[VegetarianNachos]

I have not heard back from StoneTaskin about the correct way to connect the crossovers to the iMac speakers yet. The wiring colors to the connectors to attach to the speaker connectors are different from others I have found online. I don't want to connect them incorrectly and damage my speakers. Can anyone tell me which way to connect them? On the eBay store for e-qstore-2020 they call the speaker connector side with the two circles "the back", and the other side the front. They have a different set of wire colors than the StoneTaskin ones. Also, is the connection the same for each speaker, and does it matter which crossover connects to which speaker? Thanks!

 

[PaulD-UK]

@VegetarianNachos You need to start again with the crossover wires. 😉

The plug into the R1811 is inserted correctly.
The four wires from this plug are:
Red - Left speaker +
Black - Left speaker –
Yellow - Right speaker –
Green - Right speaker +

So you have got these connected to the crossover input the wrong way - they need to be reversed.

The jumpers on the crossovers need an additional connection of the Left (4 pin) block - so 1&2 and 3&4 are both connected. The Right (5 pin) block just needs 2&3 connected, which you pic shows.

The outputs of the crossovers are connected correctly to the proper speakers in your pic #1:
In pic #1 the top crossover is Left, lower is Right.

The output wires from each crossover, going to the prongs of the speaker connection (pic #2) are:
Red - Bass speaker +
Black - Bass speaker –
-
-
Blue - Hi speaker +
White - Hi speaker –

In your pic #3 speaker connection, the connections from Top to Bottom (as you are showing it) are:

Hi speaker –
Hi speaker +
-
-
Bass speaker –
Bass speaker +

So you need to swap around either prongs OR speaker connection (only one) to plug them in correctly.

This post has the speaker connections identified correctly:

https://forums.macrumors.com/threads/diy-5k-monitor-success.2253100/post-32319156

 

[VegetarianNachos]

@VegetarianNachos You need to start again with the crossover wires. 😉

The plug into the R1811 is inserted correctly.
The four wires from this plug are:
Red - Left speaker +
Black - Left speaker –
Yellow - Right speaker –
Green - Right speaker +

So you have got these connected to the crossover input the wrong way - they need to be reversed.

The jumpers on the crossovers need an additional connection of the Left (4 pin) block - so 1&2 and 3&4 are both connected. The Right (5 pin) block just needs 2&3 connected, which you pic shows.

The outputs of the crossovers are connected correctly to the proper speakers in your pic #1:
In pic #1 the top crossover is Left, lower is Right.

The output wires from each crossover, going to the prongs of the speaker connection (pic #2) are:
Red - Bass speaker +
Black - Bass speaker –
-
-
Blue - Hi speaker +
White - Hi speaker –

In your pic #3 speaker connection, the connections from Top to Bottom (as you are showing it) are:

Hi speaker –
Hi speaker +
-
-
Bass speaker –
Bass speaker +

So you need to swap around either prongs OR speaker connection (only one) to plug them in correctly.

This post has the speaker connections identified correctly:

https://forums.macrumors.com/threads/diy-5k-monitor-success.2253100/post-32319156

Oh wow. How do these changes look now?

 

[VegetarianNachos]

Oh wow. How do these changes look now?

Turned it on and it sounds pretty good! Better than the M4 Mac mini speaker at least. Thanks so much for your help PaulD_UK! I wonder if StoneTaskin knows they are shipping these to customers wired up incorrectly?

 

[Rip57]

Thank you everyone here for detailing your experiences. I am currently sourcing parts for a relatively simple mid-2015 iMac conversion. I'm going with a R9A18 using 2 DisplayPort and will be keeping the speakers, inline wiring caps and coils for crossover.

If anyone is working on a 2DP setup, I wanted to let you know that OWC has their Thunderbolt to Dual DisplayPort Adapter on sale for $39.99 (US) with free standard shipping. Normally sells for twice that amount.

 

[braunico]

Hello everyone,
I finally “finished” my build and wanted to thank all of you on this forum for the very useful advice.
Especially PauD for all the answer and subdriver whose build inspired me.

---

Functional Requirements

• USB-C to connect a MacBook + DisplayPort for a desktop computer
• Sound
• USB-C charging
• Reuse the iMac fan (USB-C charging can draw up to 90W)
• Reuse the original power cord
• Reuse the original on/off button
• Bonus: camera support

---

Skills & Tools

• I’m not a soldering pro, so I tried to limit soldering to the simplest possible connections. I also prioritized crimping, especially for the 220V input (France).
• I don’t own a 3D printer, so I couldn’t rely on any 3D-printed parts.
• I have an engineering background, but it’s been a while, and I’m fairly new to electronics—so this project is doable by anyone. Just take your time and ask questions if you’re unsure.

---

Component Choices
Board
I chose the SA1 board because it’s:

• Cheaper
• Fanless
• No need for IR control (I’d probably lose the remote quickly anyway!)

Crossovers
I chose the Dalee 2.1 because:

• It was recommended by PaulD. as being more suitable for iMac speakers
• It’s smaller—keeping both the fan and speakers leaves very little space

Note: These don’t have jumpers to adjust sound output, should you want to.
I’m actually quite happy with the sound. I expected something terrible after reading the comments here, but it’s pretty decent (I’ve never heard how it sounds natively on an iMac, so I can’t compare).

PSU
I went with the LRS-250-24, as I wasn’t sure the 150W version would be enough for both the screen and USB-C charging.
Keep in mind that the 150W version fits perfectly (I think) in the iMac’s HDD bay. The 250W (or 350W) model also fits, but it’s bulkier and harder to secure. I used a plastic zip tie on one of the fan screws to hold it.

Joystick
I didn’t want to keep the ugly SA1 controller at the back of the case, so I used a small 5-direction joystick accessible through the RJ45 hole. More details below.

---

Some info
DDC control works

• Brightness: via BetterDisplay or MonitorControl
• Sound level: eqMac

• Brightness is really sufficient without any extra backlit (do not remember the name of the thing)

---

👀 If You’re Considering This Kind of Build
Very Limited Space

• Keeping both the speakers and fan leaves very little room. I’m not sure it’s possible to keep all four outputs of the board, but maybe.
• Because of the board’s position, finding a DisplayPort cable with a small enough or flexible enough connector was tricky. Many have large connectors. The board could be mounted slightly lower, but not much. I ended up using this one. Try to mount the board as far to the right as possible.

Watch Component Height and LCD Thickness

• I originally placed the PSU at the bottom of the case for better weight distribution and to prevent the commonly reported issue of the screen tilting forward. However, note that the iMac case isn’t uniformly deep — it’s deepest in the middle, which is where the PSU should go. The speaker height is a good indicator of what will or won’t fit (with some margin).
• The same goes for the crossover beneath the PSU. If it’s too low, the inductor coil won’t fit — the LCD panel is about 0.5 cm thick.
• I initially bought a PWM controller with the connector facing upward. Once plugged in, it was too tall. It might fit in the deepest part of the case, though.

Miscellaneous Tips

• Be careful when removing the speaker connector sides — they’re fragile and difficult to fix if broken.
• Having some cheap Wago connectors to test your wiring before soldering/crimping is very helpful — especially for the right speaker, where I had to extend the connector and re-match cables.
• The camera is tricky to fit. You’ll need to grind carefully and evenly until it fits. After reassembly, the plastic was slightly loose, so I added a small washer.
• If I were to rebuild this, I’d probably mount the PSU the other way around — with all cables at the bottom and components on top. That would make using plastic strips for securing it much easier.

---

Technical Details
Wiring Diagram
See attached image.
Joystick Wiring
The SA1 OSD controls are a bit odd:

• The Menu button on the panel doesn’t enter submenus, so I mapped it to a right movement.
• The Enter button actually goes back in the menu, so I mapped it to a left movement.

User Direction	Joystick Direction	SA1 Panel Button
LEFT	UP	ENTER
RIGHT	DOWN	MENU
MID (PUSH)	MID	MENU
UP	RIGHT	UP
DOWN	LEFT	DOWN

---

Shopping List
Basic Tools

• Multimeter — strongly recommended to test your solder joints and current direction
• Soldering materials
• Precision screwdriver kit
• Pliers (cutting + regular)
• Painter’s tape — great for temporary positioning and holding the LCD in place
• Optional: crimping tool and connectors (if you prefer crimping over soldering). You can also use dominos or Wagos.

Components

• SA1 Board
• 5-direction joystick
• 2 sound crossovers — I chose pre-wired ones
• Camera
• 24V → 12V converter (for the PWM controller)
• PWM controller: I used this one because I mistakenly ordered one with the connector facing upward and didn’t want to wait for AliExpress.
  • Must be 4-pin
  • The iMac fan requires a 12V output, so I didn’t use the output from the controller (see wiring diagram)
  • Something like this one should work better

Cabling

• Electrical cables
• 1 Molex MicroFit 3-pin — used for the power cord; can also be soldered
• Dupont connectors: some for the power button and 8-pin for the joystick
• Pre-wired JST 2.3mm 10-min cable: used because I didn’t want to destroy the original control panel one, just in case

Mounting & Misc

• Plastic standoffs — 2mm
• Rubber grommets to route cables cleanly through the closed RAM door
• Screen remounting kit
• Kapton tape
• Plastic zip ties — used to attach the PSU to one of the fan case mounts
• Optional: small piece of foam for counter pressure behind the joystick
• Optional: Superglue or hot glue gun for standoffs (though they were sturdy enough) or to reuse removed case mounts for PSU support
• Optional: isopropyl alcohol to clean the iMac case before applying mounts

---

Open Thoughts & Questions

1. I’m wondering where and how to place the PWM controller’s thermal probe — maybe on the board’s heatsink?
2. Not sure this screen can fully replace my 27" 2K gaming monitor in terms of heat and input lag — any thoughts?
3. For better thermal control, would it make sense to mount the board directly on the LCD panel so the radiator faces the iMac’s aluminum shell instead of the LCD?
4. Maybe adding thermal pads between the case and LCD would also help.

Compendium
As I scrolled a lot through this forum and Youtube I tried to organize notes about what I learned.
You can find those here: https://github.com/nicolasbraun/imac_27_conversion

 

[braunico]

I was about to ask the board if there was any way to get decent sound out of the iMac speakers using the SA1 board.

I just finished my build, using the Dalee crossovers and I find the sound more than decent. At least to watch a Youtube video. I could make a video if you like.

Oh, and don't forget to include how to keep the power button!

It's actually quite simple.
- Find the cable from the strip that is the power button on the control panel. For the SA1 it's actually written , it's the one at the bottom when looking the panel
- Find the one for GND, same it's the fifth from the top.
- Wire one of the power button cable to Power
- The other one to GND (you have to split this cable, you still need ground for the other buttons of the control panel)
- 'order' doesn't matter

cc @ItsAShaunParty

 

[shan25]

Thank you for this amazing thread. My 2015 Mac board is kaput which is great! I am new to modding so please can I have some guidance. Thanks
1. I need to connect the 2015 Mac (LM270QQ1B1) to a Macstudio using Thunderbolt. I am confused about the 10 bit colour though. Do I have to go for the twin display adapter method or can I use just single Thunderbolt/USB C connection ? This effects my choice of board. I would like full 5K/10Bit if pos.
2. I aim to keep speakers. There are two types of crossovers on The Taskin store. Prewired is best for me but seems the one with jumpers are not prewired. Which connectors do I need for that?

@braunico- you build looks great. Like the Joystick idea. Is your's a 2015 Mac? Your 2.3mm JSt links has a few types, which specific one did you use.I am a complete noob!
Thanks

 

[braunico]

@shan25

1. I need to connect the 2015 Mac (LM270QQ1B1) to a Macstudio using Thunderbolt. I am confused about the 10 bit colour though. Do I have to go for the twin display adapter method or can I use just single Thunderbolt/USB C connection ? This effects my choice of board. I would like full 5K/10Bit if pos.

No, it all depends on your choice of board. The R9A18 requires 2 DP. The SA1 or R1811 for example work fine with 1 DP or USB-C. Look at the table on the first post of this thread

@braunico- you build looks great. Like the Joystick idea. Is your's a 2015 Mac? Your 2.3mm JSt links has a few types, which specific one did you use.I am a complete noob!

- The length is up to you. I took 30cm to reuse the extra cable elsewhere but 10cm should be enough as the joystick in my build is really near the JST plug. Also I ended up not using that but if you wanna avoid crimping the dupont (can be quite hard and requires tools) you can buy prewired dupont 8P and just solder everything (keep in mind you need to split the ground though, one for the joystick, one for the on/off button) . It's way easier.
- You only need one side, since you solder the JST cables with the dupont ones or dupont connectors. So take the cheapest one "single head"
- My mac was a 2017, but all the same