Display brightness of my old iMac

[iMacConversionEnthusias]

Hi, has anybody found a solution to the issue where the backlight of the screen stays on when the HDMI device is off when using the step-down module, the PWM and the original iMac inverter. I mean a solution so that the backlight of the screen switches off automatically when the HDMI device goes off as when we use the Chinese inverter. I have my step-down module powered directly from the external PSU.

 

[csdesign3]

Hi, has anybody found a solution to the issue where the backlight of the screen stays on when the HDMI device is off when using the step-down module, the PWM and the original iMac inverter. I mean a solution so that the backlight of the screen switches off automatically when the HDMI device goes off as when we use the Chinese inverter. I have my step-down module powered directly from the external PSU.

Pull 12v from one line of the inverter board... and there you have it Use the button from the imac to the power buton board of the chinese board.

 

[SubDriver]

Hi, has anybody found a solution to the issue where the backlight of the screen stays on when the HDMI device is off when using the step-down module, the PWM and the original iMac inverter. I mean a solution so that the backlight of the screen switches off automatically when the HDMI device goes off as when we use the Chinese inverter. I have my step-down module powered directly from the external PSU.

I think you are talking about the sleep functionality of the display and the LCD driver board. I have tried a couple different options but have been unsuccessful so far. I have another option I intend to try this weekend if I get the time to do so. Will post results if successful.

The solution will reside in figuring out how to use the BLO signal from the LCD driver board to control the 3.3V signal from the step down module.

 

[iMacConversionEnthusias]

I think you are talking about the sleep functionality of the display and the LCD driver board. I have tried a couple different options but have been unsuccessful so far. I have another option I intend to try this weekend if I get the time to do so. Will post results if successful.

The solution will reside in figuring out how to use the BLO signal from the LCD driver board to control the 3.3V signal from the step down module.

Yes, correct. Some relay module to break the power supply to the step-down module based on the BLO comes to mind, but I have no idea what to search for. And we need to know the BLO voltage.

 

[SubDriver]

Yes, correct. Some relay module to break the power supply to the step-down module based on the BLO comes to mind, but I have no idea what to search for. And we need to know the BLO voltage.

Agree with both. I am going to be experimenting more with this MOSFET Driver this weekend if I get time to do so. I have it installed now, but I don’t think my BLO voltage drops enough to fully turn it off when the signal changes for sleep mode.

 

[iMacConversionEnthusias]

Agree with both. I am going to be experimenting more with this MOSFET Driver this weekend if I get time to do so. I have it installed now, but I don’t think my BLO voltage drops enough to fully turn it off when the signal changes for sleep mode.

I have been given a new idea to play with in order to achieve this, but I will play with it next week Mon or Tue because I have to order a small board - luckily, I found it locally, so I don't have to wait for more than couple of days. The idea is to use Bi-directional Logic Level Converter 5V (?) to 3.3V connected from the Chinese BLO to the Apple Inverter BLO and remove the connecting cable from the step-down module to the Apple Inverter BLO. If I am allowed to post non-Amazon links here, I can post a link for the board.

 

[PaulD-UK]

@SubDriver "I don’t think my BLO voltage drops enough..."

The R1811 spec for that is <0.5V for OFF, and >2.5-5V for ON. This is taken from the parameters for the DZ-LP-0818 CC board.

 

[SubDriver]

I have been given a new idea to play with in order to achieve this, but I will play with it next week Mon or Tue because I have to order a small board - luckily, I found it locally, so I don't have to wait for more than couple of days. The idea is to use Bi-directional Logic Level Converter 5V (?) to 3.3V connected from the Chinese BLO to the Apple Inverter BLO and remove the connecting cable from the step-down module to the Apple Inverter BLO. If I am allowed to post non-Amazon links here, I can post a link for the board.

I tried that and it did not work for me. I wrote a previous post about it. Hopefully it works for you.

 

[EddieMaster]

Hey guys! I've read through this thread a few times and I am amazed at the work that has been done! However, I am very new to this stuff and this would be the first project of this caliber for me, so I would appreciate it a ton if you guys could guide me a bit.

FYI, I bought a late 2009 iMac, but I haven't picked it up yet so I don't know the display model yet.

1. I've read stuff about using the original Apple inverter in tandem with the Chinese board for original brightness. But judging by the stuff discussed like using a step-down converter and the likes, this isn't a feasible option, right?

2. Due to the length of the thread and my inexpertice, I am a bit lost with this new stuff about step-down converters and another component I forgot the name of. I have no idea how to configure those and besides, from what I have read here, the readings are different for each monitor, right? Some help explaining it to a novice like me would be very appreciated

Thanks for reading

 

[csdesign3]

Hey guys! I've read through this thread a few times and I am amazed at the work that has been done! However, I am very new to this stuff and this would be the first project of this caliber for me, so I would appreciate it a ton if you guys could guide me a bit.

FYI, I bought a late 2009 iMac, but I haven't picked it up yet so I don't know the display model yet.

1. I've read stuff about using the original Apple inverter in tandem with the Chinese board for original brightness. But judging by the stuff discussed like using a step-down converter and the likes, this isn't a feasible option, right?

2. Due to the length of the thread and my inexpertice, I am a bit lost with this new stuff about step-down converters and another component I forgot the name of. I have no idea how to configure those and besides, from what I have read here, the readings are different for each monitor, right? Some help explaining it to a novice like me would be very appreciated

Thanks for reading

Welcome 😁

Take your time, there is already some advancements and a written PDF with instructions. You are in the right place to start your project and contribute too. Right now we know 2011 27 iMacs can be converted with success keeping the original inverter and Apple PSU/ or a power brick, as many users here feel that Chinese Controller Boards dont give the screen the right brightness levels. When your iMac and controller board arrives you will understand why we are here together 🙏

At this moment the best bet is to follow the guide in PDF... I will try helping by making a draw guide of the wiring schematic with the approval of @SubDriver ofcourse.

 

[SubDriver]

@EddieMaster and all others interested.

I have updated the guide to clarify some aspects and to add some more pictures - see the attached. I am still working on restoring the sleep functionality. I am confident I will figure it out (or maybe someone else does before me @iMacConversionEnthusias).

 

[SubDriver]

Welcome 😁

Take your time, there is already some advancements and a written PDF with instructions. You are in the right place to start your project and contribute too. Right now we know 2011 27 iMacs can be converted with success keeping the original inverter and Apple PSU/ or a power brick, as many users here feel that Chinese Controller Boards dont give the screen the right brightness levels. When your iMac and controller board arrives you will understand why we are here together 🙏

At this moment the best bet is to follow the guide in PDF... I will try helping by making a draw guide of the wiring schematic with the approval of @SubDriver ofcourse.

No approval from me required... this is a joint effort!

 

[SubDriver]

@SubDriver "I don’t think my BLO voltage drops enough..."

The R1811 spec for that is <0.5V for OFF, and >2.5-5V for ON. This is taken from the parameters for the DZ-LP-0818 CC board.

I ruled out my BLO voltage - it definitely drops far enough.

Turns out my MOSFET driver idea won't work (at least not how I was connecting it) since it requires a return lead from the load. Still some other ideas to explore yet...

 

[iMacConversionEnthusias]

@EddieMaster and all others interested.

I have updated the guide to clarify some aspects and to add some more pictures - see the attached. I am still working on restoring the sleep functionality. I am confident I will figure it out (or maybe someone else does before me @iMacConversionEnthusias).

Still waiting for the boards, may be Tuesday

 

[csdesign3]

@EddieMaster and all others interested.

I have updated the guide to clarify some aspects and to add some more pictures - see the attached. I am still working on restoring the sleep functionality. I am confident I will figure it out (or maybe someone else does before me @iMacConversionEnthusias).

@SubDriver I forget to mention, the SD card conversion needs a voltage regulator from 5v to 3.3v as shown on the shared photos... please edit

@EddieMaster and all others interested.

I have updated the guide to clarify some aspects and to add some more pictures - see the attached. I am still working on restoring the sleep functionality. I am confident I will figure it out (or maybe someone else does before me @iMacConversionEnthusias).

 

[SubDriver]

Shifting to my next attempt to restore the sleep functionality. Hoping one of these two buck converters will be successful:
- Adafruit MPM3610
- Sparkfun AP63203

Plan is to use a 12Vdc line as the Vin and use the 5V BLO line from the LCD driver board as the ENA source. It is going to take these boards at least a week to arrive... Hoping maybe they get here before this next weekend, otherwise it will be 2 weeks before I get to give them a try.

 

[EddieMaster]

Welcome 😁

Take your time, there is already some advancements and a written PDF with instructions. You are in the right place to start your project and contribute too. Right now we know 2011 27 iMacs can be converted with success keeping the original inverter and Apple PSU/ or a power brick, as many users here feel that Chinese Controller Boards dont give the screen the right brightness levels. When your iMac and controller board arrives you will understand why we are here together 🙏

At this moment the best bet is to follow the guide in PDF... I will try helping by making a draw guide of the wiring schematic with the approval of @SubDriver ofcourse.

@EddieMaster and all others interested.

I have updated the guide to clarify some aspects and to add some more pictures - see the attached. I am still working on restoring the sleep functionality. I am confident I will figure it out (or maybe someone else does before me @iMacConversionEnthusias).

Thanks a lot guys, I must have glanced over it since one of your posts had 2 or 3 PDF's haha. I'll read through it and I am super excited. Do you guys think these findings about the 2011 models are going to be applicable to my late 2009 model?

 

[iMacConversionEnthusias]

@EddieMaster and all others interested.

I have updated the guide to clarify some aspects and to add some more pictures - see the attached. I am still working on restoring the sleep functionality. I am confident I will figure it out (or maybe someone else does before me @iMacConversionEnthusias).

I can report success with the bi-directional logic board. The screen went to sleep after I switched off the Chromecast with Google TV. Initially it showed no signal then going to power saving and then off. I am attaching a very "dirty" drawing. Will prepare something better later or tomorrow (east European time) because my wife is ready to kill me

 

[iMacConversionEnthusias]

Thanks a lot guys, I must have glanced over it since one of your posts had 2 or 3 PDF's haha. I'll read through it and I am super excited. Do you guys think these findings about the 2011 models are going to be applicable to my late 2009 model?

It is all about the exact model of the screen which you will need in any way to purchase the correct Chinese board (it is about the interface cable the boards are the same otherwise). I have searched Amazon and Aliexpress and it looks like there are only two models of Chinese controller boards they sell, and both of these boards are with the same inverter board. I do not know which screen model you have but if it is from iMac A1312 it is very likely to work with all the findings from this forum. I initially started with LM270WQ1-SDE3 (from iMac A1312 mid and late year 2011 if I remember correctly) which I managed to brake physically but while it was in one piece it worked ok (with all the issues we are fighting here) and now I am with LM270WQ1-SDC2 (iMac A1312 year 2010 I think) and I do not actually see any difference between the two models.

 

[Nguyen Duc Hieu]

Thanks a lot guys, I must have glanced over it since one of your posts had 2 or 3 PDF's haha. I'll read through it and I am super excited. Do you guys think these findings about the 2011 models are going to be applicable to my late 2009 model?

The cables can be purchased separately, don't worry about that too much.

LM270WQ1-SDA2 Screen cable LM270WQ1-SDA1 LM270WQ1-SDC1 LM270WQ1-SDC2 eDP 30Pins 4 Lanes FI-X30SSL-HF Line - AliExpress 7

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

I know for sure that my iMac 2011 uses the SDE3 board.

DP_HDMI To EDP Drive board LM270WQ1-SDC2/LM270WQ1-SDA2/LM270WQ1-SDE3 Control board Kit for 2560X1440 LCD LED Screen - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[SubDriver]

I can report success with the bi-directional logic board. The screen went to sleep after I switched off the Chromecast with Google TV. Initially it showed no signal then going to power saving and then off. I am attaching a very "dirty" drawing. Will prepare something better later or tomorrow (east European time) because my wife is ready to kill me

That’s great news! I am scratching my head right now trying to understand why my attempts at using a nearly identical logic board did not work. Maybe bad soldering…

What was the source of your 5V line going to the HV terminal on the board?

 

[iMacConversionEnthusias]

That’s great news! I am scratching my head right now trying to understand why my attempts at using a nearly identical logic board did not work. Maybe bad soldering…

What was the source of your 5V line going to the HV terminal on the board?

It is another step down module from 12V to 5V and on the LV terminal the 3.3V come from the first step down module.

 

[iMacConversionEnthusias]

The cables can be purchased separately, don't worry about that too much.

LM270WQ1-SDA2 Screen cable LM270WQ1-SDA1 LM270WQ1-SDC1 LM270WQ1-SDC2 eDP 30Pins 4 Lanes FI-X30SSL-HF Line - AliExpress 7

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

I know for sure that my iMac 2011 uses the SDE3 board.

DP_HDMI To EDP Drive board LM270WQ1-SDC2/LM270WQ1-SDA2/LM270WQ1-SDE3 Control board Kit for 2560X1440 LCD LED Screen - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

I can confirm. I bought another cable as my original board was for LM270WQ1 SDE3 which I broke and the new screen is SDC2. No soldering or cutting is required. Plug and play

 

[iMacConversionEnthusias]

That’s great news! I am scratching my head right now trying to understand why my attempts at using a nearly identical logic board did not work. Maybe bad soldering…

What was the source of your 5V line going to the HV terminal on the board?

Yes, I have a battle with the soldering too. I have done lots of it in my high school some good number of years ago with no problem but now often it is a fight. For logic board I took a single wire cable because it can be soldered easier and also the holes on the board are small. The single wire can also be bend into the desired position which also helps the soldering process if you don't have a proper soldering station.

 

[SubDriver]

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