Display brightness of my old iMac

[iMacConversionEnthusias]

Thanks to you, I was able to turn my old 2010 iMac, which I was about to throw away, into a working monitor yesterday. I used an apple backlight inverter and connected the wires according to the following scheme. ➡️

China Inverter	Apple Inverter
12V	12V
12V	12V
ADJ	PWN
BL_ON	BL_On
GND	GND
GND	GND

I connected 12V and GND directly from the power supply. It`s work. But when I increase the brightness in the settings, the screen gets dimmer, and at zero brightness, it is at its highest where is the mistake?

I also want to try connecting the built-in speakers and see if I can route USB to the webcam. Is it possible?

My brightness direction works fine. I am not sure that it could be the problem/solution, but in my setup the 12V and GND to the original inverter are coming from the Chinese board, and not directly from the external PSU. I use PWM module as well.

Just to brag about it the brightness is quite high for me at 100% in my setup, so I actually keep it at 70-75% as it uses less power (70-75W depending on what's on the screen - lighter colours use more power), and it is easier on the eyes At full brightness the power consumption of my setup is 105-110W.

 

[iMacConversionEnthusias]

So I have been using 2 40/40 mm 12V permanent speed turbine fans. One to cool down the Chinese board and one for the original inverter. I noticed that the screen itself gets hotter in the top middle compared to the top right side (top left is hotter because of the inverter). It looks logical as positioned at the top middle and going to top left and top right is the build in board of the screen.

I have been playing with fan speed controllers and the original fans without much luck, and I realised that if I remove the small fan from the original HDD blower and put in the blower one of my 40/40 turbine fans to blow and channel the air over the Chinese board (mine is right on top of the bracket) and towards the top middle of the screen this way it will cool down both the Chinese board and the build in screen board. It will also bring cool air from outside through the plastic grid at the back of the screen box and it will drive the hot air out though the top of the box. So, I did it and it decreased the inside temperature by 4-5C. Is has been running for just over 3 hours and the temp is bellow 42C. Initially, before all the fine tunings the temp was going to 50C. After adjusting the inverter fan to blow directly at the 6 inductors of the invertor the temp decreased few degrees and today after the fan changes another few, and now I am good with the heat

 

[nktkiev]

Hi Nktkiev,

thank you very much for your post. This is really interesting, because there seems to be a way to use the original Apple inverter with a 2010 model "out of the box"! I assume you are getting full brightness then (just with the reversed OSD slider, which seems like a minor problem to me)? Would you mind sharing the exact screen model an board you used? Did you experience any heat issues with the inverter yet?

Concerning your questions: The speakers may be powered by the 4-pin blue connector and the cable of the webcam can be cut off and connected via USB. The USB port on the board, however, is just providing 5V power, no data, at least to my knowledge.

Hi Imacker2011,

It looks like I’m getting full brightness, just like on the original iMac. At least when comparing it to a similar iMac, there’s no noticeable difference in brightness. See the foto, at foto is it left display. Right now, I’m using +-60% of max brightness.

As for heat, I don’t see any issues. The monitor gets warm but not hot.

On Friday, I connected the webcam—I found the solution on the forum, on this page. I also connected the speakers. The sound is loud, but the quality isn’t great. Maybe the tweeters need a capacitor. I’ll try that later when I have it.

Right now, the monitor is running with a Mac Mini M1. I noticed the image flickered a few times—not sure if the issue is with the Mac Mini, the cable, or the monitor itself. Yesterday, with a 2014 Mac Mini, I didn’t have any problem. I’ll test it for a few weeks to have more information.

 

[nktkiev]

My brightness direction works fine. I am not sure that it could be the problem/solution, but in my setup the 12V and GND to the original inverter are coming from the Chinese board, and not directly from the external PSU. I use PWM module as well.

I’ll try to connect 12V and GND through the Chinese board. Right now I don’t want to disassembly the monitor again. Maybe I’ll do it later.

 

[SubDriver]

@nktkiev. Nice it worked for you straight from the LCD driver board. You are one of the luckly few to have success like this.

Of note, your inverter looks much different than mine (a 2011 model). I did some searching online. Your inverter is actually from a 2009 27 inch iMac (see pictures below). Apple used 3 different inverter model numbers for their 2009, 2010, and 2011 iMacs. The 2009 and 2010 inverters look very similar. The 2011 inverter looks much different. And I have even seen some differences within the models themselves despite having the same number (likely just different manufactures?).

2009: V267-601hf

2010: V267-602hf

2011: V267-604hf

I'm beginning to think maybe the 2009 inverter is compatible to the Chinese LCD driver board output directly.

Additionally, it wouldn't surprise me if Apple carried some of the 2009 inverters and LCD panels forward into the low end (Core i3 for example) 2010 models. I have nothing to prove this, but it would be logical to do so and might explain how someone with a 2010 iMac had success with a direct connection from the LCD driver board to the inverter.

Anyone else out there have a 2009 (V267-601hf) inverter that might be able to test this theory out?

 

[SubDriver]

I HAVE SOLVED THE SLEEP FUNCTIONALITY!!!

Sorry I have been away from the thread for so long... Life happens... everything about this project was basically put on hold for the last month.

To solve the sleep functionality, I used this buck converter. I connected the extra 12 Vdc and ground lines from the LCD driver board to the Vin and GND wire connector, the BLO line from the driver board to the EN connection, and a line from the iMac inverter ENA connection to the 3V3 output connection (do not need a output ground line).

My display now sleeps, goes into power save mode, and wakes up correctly according to the status of the connected computer.

I am nearly complete with my conversion now. I am getting a different amplifier for my speakers and will install it in the coming days - that will be the final step. I found out the 2011 iMac amplifier for each speaker is 17W. As such, I am buying an amp rated for 30W (2x15W channels) to install and use in hopes it will deliver better sound quality than the measly 2W amps I have now.

I will post some pics and update my guide once I complete the project in the coming days.

 

[SubDriver]

Can you post the schematics please.

Here are some links to websites that have schematics - this way you can ensure to find the one that is applicable to your model.

IMAC SCHEMATICS

IMAC SCHEMATICS - <p><br></p>

appleschematic.com

https://www.scribd.com/document/398541208/820-2828-iMac-27-Mid-2011-model-A1312

https://dravecky.net/?section=10

820-2828_iMac 27, Mid 2011, model A1312 - PDFCOFFEE.COM

8761. ALL RESISTANCE VALUES ARE IN OHMS, 0.1 WATT +/- 5%. 2. ALL CAPACITANCE VALUES ARE IN MICROFARADS. 3. ALL CRY...

pdfcoffee.com

Bioshelp - Apple Schematic

bioshelp.com

Hope this helps.

 

[SubDriver]

So I have been using 2 40/40 mm 12V permanent speed turbine fans. One to cool down the Chinese board and one for the original inverter. I noticed that the screen itself gets hotter in the top middle compared to the top right side (top left is hotter because of the inverter). It looks logical as positioned at the top middle and going to top left and top right is the build in board of the screen.

I have been playing with fan speed controllers and the original fans without much luck, and I realised that if I remove the small fan from the original HDD blower and put in the blower one of my 40/40 turbine fans to blow and channel the air over the Chinese board (mine is right on top of the bracket) and towards the top middle of the screen this way it will cool down both the Chinese board and the build in screen board. It will also bring cool air from outside through the plastic grid at the back of the screen box and it will drive the hot air out though the top of the box. So, I did it and it decreased the inside temperature by 4-5C. Is has been running for just over 3 hours and the temp is bellow 42C. Initially, before all the fine tunings the temp was going to 50C. After adjusting the inverter fan to blow directly at the 6 inductors of the invertor the temp decreased few degrees and today after the fan changes another few, and now I am good with the heat

Good to hear you have found a way to manage the heat your setup is generating.

I still haven't experienced any significant heat problems. I don't even need a fan for the Chinese board. Hopefully it stays this way.

 

[SubDriver]

My brightness direction works fine. I am not sure that it could be the problem/solution, but in my setup the 12V and GND to the original inverter are coming from the Chinese board, and not directly from the external PSU. I use PWM module as well.

Just to brag about it the brightness is quite high for me at 100% in my setup, so I actually keep it at 70-75% as it uses less power (70-75W depending on what's on the screen - lighter colours use more power), and it is easier on the eyes At full brightness the power consumption of my setup is 105-110W.

Are you using both of the 12V lines from the Chinese board to provide power to the inverter? Or are you just using one?

In my setup, the 12V to the inverter is coming from the original iMac power supply in the same manner as it was prior to the conversion (two 12V lines directly from the PSU to the inverter). I am using the two 12V lines from the Chinese board to provide power to the PWM module and the buck converter for the ENA signal (described a few posts above) - thus, much lower demand on the Chinese board, which likely explains my lower temps here.

I am beginning to think that your heat issues might be due to the fact all the power demands are being placed on the external PSU and the Chinese board. Whereas using the original iMac PSU provides me no fewer than 4-5 different 12V lines, each capable of providing 5+ amps. Power being spread over several lines won't generate the same amount of heat.

 

[SubDriver]

Ok, here is the image from the Ali shop customer:

The inverter in the picture is either a 2009 or 2010 inverter (see the details I provided a few posts above). The picture isn't good enough to see the actual model number to dtermine if it is a -601HF or -602HF.

 

[imacker2011]

Thank you @nktkiev and @SubDriver for the photo documentation and the extensive research. Looking at my own Apple inverter, it seems that I have the 2010 version (inferring from the model number on it). It was an iMac 2010 i7@2,93GHz.

Since nktkiev's inverter seems to be the 2009 version, did anyone already successfully connect the Chinese board directly to the 2010 version (V267-602hf) gaining full brightness? I would probably try in the near future, but I am not sure about the actual risk. Is it possible to destroy something (given all cables properly connected according to nktkiev's scheme)? At the moment, I am using the converted monitor on a daily basis for work and I don't want to break it.

As regards sound, I also read that some kind of high-pass filter is done by the Apple motherboard, so it would make sense to include a capacitor - which one are you choosing? I also thought about just connecting the sound output to the original 3,5mm jack on the backside of the case...in order to hook it up to a hifi system.

 

[SubDriver]

Thank you @nktkiev and @SubDriver for the photo documentation and the extensive research. Looking at my own Apple inverter, it seems that I have the 2010 version (inferring from the model number on it). It was an iMac 2010 i7@2,93GHz.

Since nktkiev's inverter seems to be the 2009 version, did anyone already successfully connect the Chinese board directly to the 2010 version (V267-602hf) gaining full brightness? I would probably try in the near future, but I am not sure about the actual risk. Is it possible to destroy something (given all cables properly connected according to nktkiev's scheme)? At the moment, I am using the converted monitor on a daily basis for work and I don't want to break it.

As regards sound, I also read that some kind of high-pass filter is done by the Apple motherboard, so it would make sense to include a capacitor - which one are you choosing? I also thought about just connecting the sound output to the original 3,5mm jack on the backside of the case...in order to hook it up to a hifi system.

I tried connecting directly to my 2011 inverter (-604HF) from the driver board initially for my conversion and it did not damage the inverter sending 5 Vdc and 39 KHz instead of the required 3.3 / 13.3.

Of course there is always the chance I was just lucky.

 

[bmwm3343ps]

Hello guys! I experimented trying to use the original fans with a Pwm Fan Controller (the one with 3 fan output) with no luck. Then I saw this thread ( https://forums.macrumors.com/thread...-using-an-external-cable-or-usb-port.2407334/ ). If anyone wants to use the original fans there is the solution.

 

[iMacConversionEnthusias]

Hello guys! I experimented trying to use the original fans with a Pwm Fan Controller (the one with 3 fan output) with no luck. Then I saw this thread ( https://forums.macrumors.com/thread...-using-an-external-cable-or-usb-port.2407334/ ). If anyone wants to use the original fans there is the solution.

Hi, does it work with the board with the 3 fan output.

 

[bmwm3343ps]

Hi, does it work with the board with the 3 fan output.

No. The original imac fans do not work as normal 4pin fans do.

 

[Monja96]

My first attempt didn't go well; it seems I got confused with the schematic to follow.

I have the PWM board, two step-down converters, the original inverter, the original PSU, and another external one.
What schematic should I follow? Do you recommend using the Apple PSU or the external 12V one? I've seen that several people have posted some images, but I'm not sure which schematic to follow or which one is recommended

 

[iMacConversionEnthusias]

My first attempt didn't go well; it seems I got confused with the schematic to follow.

I have the PWM board, two step-down converters, the original inverter, the original PSU, and another external one.
What schematic should I follow? Do you recommend using the Apple PSU or the external 12V one? I've seen that several people have posted some images, but I'm not sure which schematic to follow or which one is recommended

Hi, what happened, what is the result? You have to decide which way to go with the schematics. There is no recommended schematic per se. It depends on what you want to achieve as a result. About the PSU again it depends on your target. I am currently using external PSU 12V/10A because the original PSU is broken, but I am waiting for the boards to convert another iMac with good original PSU and I will try to use it. I have posted few messages in this forum about the temperature inside the box and I do not know if it will be better or worse with the original PSU, but I will definitely try it. My current converted iMac has been working with no problem for two weeks now. However together with the boards I mentioned I will receive a new fan and a new single board but dual step-down module 12V to 3.3V/5V to try to achieve better results by replacing my two current step-down modules.