DIY 5k Monitor - success :-)

[PaulD-UK]

I would be more worried about ventilation holes allowing the noisy PSU to be audible.
EM interference is more a problem with unshielded cable lengths, rather than small holes in the shielding enclosure.

Does the OSD give any indication of the T19's colour mode?
Some pics would be nice when it's all done.

 

[baggiero]

I would be more worried about ventilation holes allowing the noisy PSU to be audible.
EM interference is more a problem with unshielded cable lengths, rather than small holes in the shielding enclosure.

Does the OSD give any indication of the T19's colour mode?
Some pics would be nice when it's all done.

Not on the popover but I think the test image at least says no subsampling.

 

[Edwin Heijnen]

Hello all,

After reading this forum I also tried to convert my old iMac 27inch 5K late 2014 into a monitor for my MacBook Air M3.
I took the panel of my iMac very carefully via the instructions on the ifixit website. (was very simple because of the clear instructions)
I bought the Haijing T-18 driver board

After connecting my MacBook the power led goes from red to green, and in the MacBook the extra screen pops up.
Unfortunately the panel stays black.

The left picture is copied from Aliexpress website
The richt picture is my situation
As you can see, it is exactly the same.

Does someone know what is wrong?

Thanks for your help

 

[fhall1]

Try plugging in your backlight cable (with the white plastic connector) the other way. Take it out and turn it 180 degrees.

 

[Edwin Heijnen]

I tried to flip it, unfortunately same result, makes no difference.

 

[PaulD-UK]

The pic you posted looks right - the outer red backlight wire from the T18 plus into the outer grey wire on the screen backlight cable.
Since the Mac shows the monitor is present, it presumably is a backlight problem.
On the screen when it is powered up by the Mac can you see any image if you shine a torch close to the screen?
If you do see something then it is a b/l or b'l cable problem.

EDIT EDIT EDIT:
I've screenshotted a video of a test of the T18 and it shows the B/L cable attached to a different socket, the outermost one on the board...

 

[Edwin Heijnen]

The screen is totally black also if I shine with a torch.
Does that mean the backlight is not working?

 

[PaulD-UK]

Here's another pic.
Plug your B/L cable as this one is.

 

[Edwin Heijnen]

And with mine the backlight cable is attached at another socket. I can try to take it out and put it in te outside socket

 

[Edwin Heijnen]

And with mine the backlight cable is attached at another socket. I can try to take it out and put it in te outside socket

yeeeeeeeeeaaaaaaaaah it worked. So many thanks!!!!!!!!!!!!!
Somebody in China made a mistake I guess

 

[PaulD-UK]

It looks like you have a 4 pin plug, and the correct socket is 5 pins, so the pics on the web seem to show the left four pins are used, with the outermost (right) pin of the socket left unconnected.

 

[Edwin Heijnen]

Yes, that is exactly what I did, and it worked, So happy, you saved my Sunday ;-)

 

[hiwdu8]

Hello All,

Great thread! Thank you all for posting, I learned a lot of helpful tips along the way.

I've been working on my own build and the monitor will turn on and off at random times for no reason. Did anyone else experienced similar behavior?

My setup:
LCD Panel: LM270QQ1 SDF1
Driver: R1811
DZ-LP0818 50W current Board as recommended here.

I tried with and without the current board and I'm getting same behavior. I'm using the power source that came with the R1811 driver.
I tested the R1811 on my friend's LCD panel (LM270QQ1 SDA2) and it works great so I know that the driver should be fine.

Any help would be greatly appreciate since I put in a good amount of $$ and can't make use of the monitor

 

[baggiero]

Hello All,

Great thread! Thank you all for posting, I learned a lot of helpful tips along the way.

I've been working on my own build and the monitor will turn on and off at random times for no reason. Did anyone else experienced similar behavior?

My setup:
LCD Panel: LM270QQ1 SDF1
Driver: R1811
DZ-LP0818 50W current Board as recommended here.

I tried with and without the current board and I'm getting same behavior. I'm using the power source that came with the R1811 driver.
I tested the R1811 on my friend's LCD panel (LM270QQ1 SDA2) and it works great so I know that the driver should be fine.

Any help would be greatly appreciate since I put in a good amount of $$ and can't make use of the monitor

Albeit with no real personal experience to back it up, I’d suggest trying an alternative power supply?

 

[PaulD-UK]

The R1811 board is very sensitive to variations in its 24v power feed.

I've found that other equipment located nearby on the same mains power circuit can cause a momentary blackout when they are switched on, as this causes fluctuations in the mains voltage.

A better PSU with output voltage smoothing, and preventing the switch-on interference from other equipment nearby should stop this.

 

[erihp]

The R1811 board is very sensitive to variations in its 24v power feed.

I've found that other equipment located nearby on the same mains power circuit can cause a momentary blackout when they are switched on, as this causes fluctuations in the mains voltage.

A better PSU with output voltage smoothing, and preventing the switch-on interference from other equipment nearby should stop this.

Perhaps in PSU that is included in ever iMac would fare better!

I've seen a couple mods with boost converters for 12v imacs to 24v controllers. and i know some inacs have 24v supplies. I'd thinknit'd be enough juice, if it can power the factory screen as well as the logic boards and peripherals!

 

[hiwdu8]

Thank you all for your great input. You all where right. I played around with the display settings and lower the brightness and the momentary blackouts went away.

My iMac PSU has 12v unfortunately...If I go with a booster I still need to find a good one. Does anyone recommend a good booster 12v to 24v or a better PSU for the R1811 board?

Edited: I've seen people recommend this power supply https://www.amazon.com/gp/product/B083K71SM8/ref=ox_sc_act_title_1?smid=AA0YO4F2UD50F&psc=1 I couldn't find anyone that tried a booster with the iMac original PSU.

 

[fhall1]

Perhaps in PSU that is included in ever iMac would fare better!

I've seen a couple mods with boost converters for 12v imacs to 24v controllers. and i know some inacs have 24v supplies. I'd thinknit'd be enough juice, if it can power the factory screen as well as the logic boards and peripherals!

I got this one and it seems to be working great - no drops or flickers or whatever. https://www.amazon.com/gp/product/B083K71SM8

 

[erihp]

Waiting for this, hoping it will work!

HQRP DC 12V Step Up to 24V 10A Boost Converter 240W DC Voltage Regulator Power Converter Waterproof Module Transformer for RV, Solar System, Water Pump, Golf Cart Club Car

HQRP DC 12V Step Up to 24V 10A Boost Converter 240W DC Voltage Regulator Power Converter Waterproof Module Transformer for RV, Solar System, Water Pump, Golf Cart Club Car

www.amazon.com

 

[baggiero]

So, it's basically done, and I'm really pretty pleased with the layout - various bits of reuse and bodging! Managed to fit a cut-down electrical backbox grommet (pic2) around the DP-TB cable exit through the ex-ethernet port. The screen's great (maybe a touch blue-grey?) but there's something majorly off with the audio. Playing back a short .MOV I got maybe a tiny bit of dialogue (<0.1s) and then maybe a bit of stutter but otherwise silence. Am going to test hooking up headphones to the jack and see if the board is actually extracting audio from the DP properly as a start. Have tested continuity between board terminals and inputs to the crossovers.
Any other thoughts/suggestions?

 

[PaulD-UK]

Nice build.
Did you take a hi-res pic of the back of the T19 - I haven't seen it before and I'm interested in the silkscreen iDs of the pins.

As to the sound problems, @i486dx2-66 posted the audio chip datasheet info for the T18, but the T19 is the same as far as I can see from the manufacturer's pics, and unusually it specifies only 8 ohm speakers.

The original iMacs and iMac Pro use a similar sort of digital amplifier, also specified for 8 ohms, but also allowing the use of 4 ohm speakers. The R1811/R9A18 audio amp is the same, quite happy with 4 ohm iMac speakers.

The T18/19 amplifier has overload cutout protection, and I wonder if the lower resistance 4 ohm speakers look like an overload situation to the amp, and causes it to shut down?

That's a complete guess, but as a test you could try running the T19 audio output with 8 ohms - temporarily connecting both iMac speakers in series (disconnecting the crossovers), or using hifi external 8 ohm speakers if you have access to a pair.

 

[PaulD-UK]

Hi, it occurs to me that there might be something funky going on with the crossover jumpers, your picture shows them all 'on'.
Here is my attempt to analyse what they do and what effect they may have, all done from photos, so no guarantee of exactitude...
Try removing jumpers A and B, which should bring the inductor and capacitor C3 into play, and that will increase the impedance/resistance the speaker presents to the audio amp.

 

[baggiero]

Gave the jumper-removal method a try but no change. The OSD doesn't seem to have any option to show colour mode or depth unfortunately. Am thinking the display is just looking a bit too high-colour-temp maybe - OSD says 7500K so I could just try turning it down a bit. Will try some old Mission bookshelf hi-fi speakers (pretty sure they're 8Ohm)

[edited] - the board (and the screen in front of it) is getting SERIOUSLY hot even with the heatsink on the facing-away-from-the-screen face - bordering on too hot to touch and to a level where I'm a little worried about plastic melting ... Might it be perhaps because it's because it's being supplied 12V rather than 24?

 

[PaulD-UK]

The jumper settings won't make a huge difference, but disconnecting all four jumpers will mean that only the low frequency speaker will be connected, which is sure to be 4 ohms so if it still fails like that then a test with 8 ohm speakers, connected with all 4 jumpers removed (or no crossover at all) would be the next thing.

I wouldn't have thought the supply voltage makes much difference, as all the various boards all work at 12v for the backlight, and 5v/3.3v for all the IC's on the board.
Only the USB-C PD charging circuit uses 20v, and that produces no heat if it's unused, or not there...

The main video driver chip on the all these boards can go up to 65ºC before there is an overheat situation, but that is too hot for sustained use.
Several previous builders have fitted a fan to blow air over the heatsink.
I fitted a proper fan exhaust system for my R1811 build, which runs at very low speed, and I never feel any warmth whatsoever on the case exterior or air vent.
The screen panel in front of the board is about 2º C warmer than the edge of the screen.

Hopefully some of the other readers here who use a T18 board at 12v, like @jag001, would tell their experience.

 

[PaulD-UK]

To members who have compiled lists of the various boards used for DIY monitor conversions, like @i486dx2-66 and @sebko200, yet another pair of new boards seem to have appeared...

With similarities to the Haijing T18 and T19, and with the same prefix as the JRY-W9CUHD-AA1... we now have the
JRY-W9RQUHD-FA1, and the JRY-W9RQUHD-SA1, from Shenzhen JRY Xinxian Technology Co., Ltd.

iMac 27

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

There are pictures of each board under the Specifications>View More tab, and a description:

The JRY-W9RQUHD-FA1 board is a UHD display driver board
Built in MPRT dimming function, maximum resolution
5120X2880/60HZ
*supports eDP screen interface signal output.
*supports multiple OSD languages to choose from.
*supports HDMI 2.1, HDCP supports version 2.3.
*supports DP1.4 signal input.
*supports headphone and speaker functions.
*supports OD acceleration function.
*supports Freesync functionality
*supports HDR function.

https://ae01.alicdn.com/kf/Se749cf417ae74efb9ff955f75d49bc64z.png

The JRY-W9RQUHD-SA1 board is a QUHD display driver board
Built in MPRT dimming function, the most efficient
The high resolution is 5120X2880/165Hz.
*Support EDP screen interface signal output.
*Supports multiple OSD languages to choose from.
*Supports HDMI 2.1, HDCP supports version 2.3.
*Supports DP1.4 signal input.
*Supports USB mouse, keyboard, and other functions
*Supports headphone and speaker functions.
*Supports TYPE-C video input and provides external 90W power supply.
*Supports OD acceleration function.
*Supports Freesync functionality.
*Supports HDR functionality.

https://ae01.alicdn.com/kf/S0983ec39a9c3487a8d7f296ccc8870ff1.png

With typos/misleading differences in the listings and pics - The high resolution is 5120X2880/165Hz, and Both driver boards can achieve 5120X2880/165Hz. 10BIT, Supports HDMI2.1 etc, it remains to be seen what they actually can do.
The screenshot pic shows HDMI 5K RGB 10-bit using Windows, so presumably they are an advancement over the earlier boards?

No IR remote, however.