Hello, I am thinking of doing the same, converting my 27inch iMac into an external monitor by means of an LCD controller board. I have done this before to a laptop screen and am aware of the whole dimmed brightness. Have you had success with the original backlight board? and for keeping things cool, maybe it would be possible to reuse the stock heatsink/pipes over whatever component is getting hot and attach a PC fan to the inside of the iMac to blow over the fins?
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display brightness of my old iMac
- Thread starter zoran
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What stock heatsink are you talking about?
Those current regulator chips are quite small.
So you meant the Apple LCD backlight board was fried, the Aliexpress kit is still working?
I was assuming that most people doing this would be dismantling an iMac and thus could keep the stock cooler components, and attempt to utilise those to cool the heat generating components with some thermal pads/paste.
Quote: "I was assuming that most people doing this would be dismantling an iMac and thus could keep the stock cooler components, and attempt to utilise those..."
For post-2014 5K 27" iMacs you don’t need to assume:
forums.macrumors.com
Most people haven’t bothered with cooling solutions.
My build did - with a 21.5" iMac fan :
forums.macrumors.com
This builder used the stock fan:
forums.macrumors.com
Quote: "Have you had success with the original backlight board?"
Three of the available LED video driver boards - R1811, R9118 and U49 - come with additional backlight constant current driver boards.
The U49 kit (5K 8-bit) comes with one as standard.
The R9A18 and R1811 boards (5K 10-bit) have a backlight drive on the board as standard, but there is an additional DZ-LP0818 board available as an extra.
This may also work with other T18/T19 boards - I have no information on that.
stonetaskin.com
Its main purpose is to boost the backlight of 'remanufactured' AliExpress 27" 5K screens where they have been rebuilt after the glass has been broken or the LED has been replaced.
These screens often don't perform like new and need to be boosted...
If you have a good condition stock Apple 5K screen then the brightness is usually good enough for most people.
A standard R1811 has been measured at 332 nits, but with the DZ-LP0818 it was boosted to 461 nits.
This obviously varies a bit from screen to screen.
For post-2014 5K 27" iMacs you don’t need to assume:
DIY 5k Monitor - success :-)
My "latest Macs" are a heavily upgraded 2009 Mac Pro (6c CPU, M.2 SSD, USB 3, RX580...) and more recently a 12c 2013 Mac Pro with an eGPU (Vega 56) - both machines with more than enough CPU power, GPU power and RAM for my needs, but I long aspired to upgrade to a nice 5k monitor to replace my...
forums.macrumors.com
Most people haven’t bothered with cooling solutions.
My build did - with a 21.5" iMac fan :
DIY 5k Monitor - success :-)
My build is now more or less complete. Haha, I started out thinking minimally, but that's not how things have turned out - 6.66 Kg is the number of the beast, well its weight... 1. R1811, bought from Chinese seller on eBay UK. This is mounted so that access to the cable ports are retained...
forums.macrumors.com
This builder used the stock fan:
DIY 5k Monitor - success :-)
The time has finally come for me to convert my 2017 5K iMac. What I have yet to find is a conversion that keeps the stock iMac look. This is what my project aims to achieve. The stock look is achieved using the Thunderbolt 3 ports as input for both USB-C and DisplayPort. The USB A ports and...
forums.macrumors.com
Quote: "Have you had success with the original backlight board?"
Three of the available LED video driver boards - R1811, R9118 and U49 - come with additional backlight constant current driver boards.
The U49 kit (5K 8-bit) comes with one as standard.
The R9A18 and R1811 boards (5K 10-bit) have a backlight drive on the board as standard, but there is an additional DZ-LP0818 board available as an extra.
This may also work with other T18/T19 boards - I have no information on that.
High-quality DIY Universal Driver Board 50W Current Board DZ-LP0818 R
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...
Its main purpose is to boost the backlight of 'remanufactured' AliExpress 27" 5K screens where they have been rebuilt after the glass has been broken or the LED has been replaced.
These screens often don't perform like new and need to be boosted...
If you have a good condition stock Apple 5K screen then the brightness is usually good enough for most people.
A standard R1811 has been measured at 332 nits, but with the DZ-LP0818 it was boosted to 461 nits.
This obviously varies a bit from screen to screen.
Last edited:
I would like to attempt this with the potential overheating issue in mind, would you be able to provide more detail on which pins on the inverter board (original backlight board) you soldered the wires to from the LCD controller board? I think the BLO and ADJ are pin 1 and 3 respectively but I see you connected all the wires in the image.
Have you tried it?
I would be very interested in the solution with the original inverter board.
I ordered an old iMac2010 for 80€ on eBay and am thinking about ordering a controller board on Amazon:
https://amzn.eu/d/dyfa42d (Germany).
The video on Amazon reports that if the power supply is strong enough >4A, there should be no problems with the brightness.
Another video
also reports a problem-free installation without using the original inverter board.
I would be very interested in the solution with the original inverter board.
I ordered an old iMac2010 for 80€ on eBay and am thinking about ordering a controller board on Amazon:
https://amzn.eu/d/dyfa42d (Germany).
The video on Amazon reports that if the power supply is strong enough >4A, there should be no problems with the brightness.
Another video
also reports a problem-free installation without using the original inverter board.
yes, right - he used the inverter which comes with the control board.
However, others have used the chinese control board but connected to the original inverter:
„Thank you very much seller! Everything is clear and fast. Connected, everything works. Brightness is more than sufficient. The main thing is that the board works for a long time. It's a pity that you can't connect the standard iMac speakers. I will publish the picture of the backlight connector. On pen 1 red wire from the board.“ Source Ali Express Comments of souch a board
However, others have used the chinese control board but connected to the original inverter:
„Thank you very much seller! Everything is clear and fast. Connected, everything works. Brightness is more than sufficient. The main thing is that the board works for a long time. It's a pity that you can't connect the standard iMac speakers. I will publish the picture of the backlight connector. On pen 1 red wire from the board.“ Source Ali Express Comments of souch a board
10,39€ | 27 ''imac a1312 a1316 a1407 2k LCD-Controller Laufwerks platine Monitor Display-Kit für lm270wq1 a2 c2 e3 b1 b3 Bildschirm test Motherboa
10,39€ | 27 ''imac a1312 a1316 a1407 2k LCD-Controller Laufwerks platine Monitor Display-Kit für lm270wq1 a2 c2 e3 b1 b3 Bildschirm test Motherboa
a.aliexpress.com
Attachments
FYI: in this post https://de.ifixit.com/Antworten/Ans...e+values?permalink=answer-798834#answer798834
someone stated, that he has solved the brightness problem:
„
You need to buy a 12v->5V converter for the Arduino. I have make a little code to convert the 5-0V(low to hight) signal of the Chinese controller to a correct signal PWM (5V, 13kHz) for the inverter. It'a now possible to use the native brightness control of the Chinese controller.
With the code I make, yon have to connect the BLO of the controller to the pin 1 of the inverter, and the ADJ to the pin 3 of the inverter.“
Here a link to the pinout (not tested)
hqlaptoprepair.co.uk
Hope this helps. Maybe someone can try it and Investigate further ?
someone stated, that he has solved the brightness problem:
„
You need to buy a 12v->5V converter for the Arduino. I have make a little code to convert the 5-0V(low to hight) signal of the Chinese controller to a correct signal PWM (5V, 13kHz) for the inverter. It'a now possible to use the native brightness control of the Chinese controller.
With the code I make, yon have to connect the BLO of the controller to the pin 1 of the inverter, and the ADJ to the pin 3 of the inverter.“
Here a link to the pinout (not tested)
iMac A1312 PSU Pinout – HQ Laptop Repair
hqlaptoprepair.co.uk
Hope this helps. Maybe someone can try it and Investigate further ?
Take a penny. Leave a penny.
I managed to use the original apple inverter board for full brightness control together with the chinese control board.
In this scenario the chinese inverter which comes with the controll board is not used.
The pins are basically described on both boards.
From the China control board the ADJ goes to PWN and the BL_ON to the BL_ON of the Apple inverter. Furthermore, the 12 V pins and the GND pins are connected to the respective 12 V pins and the GND pins on the Apple inverter.
The brigthness can also be regulated via the menu of the Chinese Controller board. However, the adjustment bar in the menu is now strangely inverted. So that the maximum screen brightness corresponds to 0% at the adjustment bar of the brightness in the menu.
The maximum brightness should be a voltage of 3.25 V. I was also able to measure this with the multimeter.
Everything works for now. Let's see if it stays stable when the screen is on for several hours.
I have used a iMac 2010 with a LG LM270wq1 SDC2 Screen. I orderd the Control Board Version with Display Port and HDMI
| DP_HDMI Zu EDP Stick bord LM270WQ1-SDC2/LM270WQ1-SDA2/LM270WQ1-SDE3 Control board Kit für 2560X1440 LCD LED Screen
Further I have used a 12V 5 A Power supply.
I managed to use the original apple inverter board for full brightness control together with the chinese control board.
In this scenario the chinese inverter which comes with the controll board is not used.
The pins are basically described on both boards.
From the China control board the ADJ goes to PWN and the BL_ON to the BL_ON of the Apple inverter. Furthermore, the 12 V pins and the GND pins are connected to the respective 12 V pins and the GND pins on the Apple inverter.
The brigthness can also be regulated via the menu of the Chinese Controller board. However, the adjustment bar in the menu is now strangely inverted. So that the maximum screen brightness corresponds to 0% at the adjustment bar of the brightness in the menu.
The maximum brightness should be a voltage of 3.25 V. I was also able to measure this with the multimeter.
Everything works for now. Let's see if it stays stable when the screen is on for several hours.
I have used a iMac 2010 with a LG LM270wq1 SDC2 Screen. I orderd the Control Board Version with Display Port and HDMI
| DP_HDMI Zu EDP Stick bord LM270WQ1-SDC2/LM270WQ1-SDA2/LM270WQ1-SDE3 Control board Kit für 2560X1440 LCD LED Screen
14,19€ | DP_HDMI Zu EDP Stick bord LM270WQ1-SDC2/LM270WQ1-SDA2/LM270WQ1-SDE3 Control board Kit für 2560X1440 LCD LED Screen
14,19€ | DP_HDMI Zu EDP Stick bord LM270WQ1-SDC2/LM270WQ1-SDA2/LM270WQ1-SDE3 Control board Kit für 2560X1440 LCD LED Screen
a.aliexpress.com
Further I have used a 12V 5 A Power supply.