Display brightness of my old iMac

[csdesign3]

During the today lauch time, i tested the 12 6Amp porwer brick and dont work like we expected (the power brick complete turns off the led and dont provide power). I have to decide the way to go (Original PSU or 8Amp power brick). I dont like the ideia to add a push pull button, i prefer to keep the stand button to turn Chinese controller... @SubDriver @iMacConversionEnthusias

In the mean time, i have complete the holes at the back for the DP, HDMI and USB Upstream Ports, i like the way it ends

I need to buy a Headset jack that cutoff speakers when connect the audio jack, and design/print a part to secure the 4 USB ports at back inside...

 

[csdesign3]

Hi, can somebody tell me how to wire the original HDD fan. I measured it and it seems to be good then I tried to connect it to 5V and to 12V with various combinations of suppling the V to the 4 wires. By the little I can see at the board behind the sticker I saw that the most right wire is VCC and the one to the left is GND and that's how much I could see. I read that 2 of the wires are for regulating the speed so I was thinking that if I short circuit them (the 2 most left wires) and supply the V to the VCC and to the GND wires it should work but it did not. Thanks.

I thing you need a module to power and control the fan, this one has a probe to regulate the fan spining

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[csdesign3]

Hi, can somebody tell me how to wire the original HDD fan. I measured it and it seems to be good then I tried to connect it to 5V and to 12V with various combinations of suppling the V to the 4 wires. By the little I can see at the board behind the sticker I saw that the most right wire is VCC and the one to the left is GND and that's how much I could see. I read that 2 of the wires are for regulating the speed so I was thinking that if I short circuit them (the 2 most left wires) and supply the V to the VCC and to the GND wires it should work but it did not. Thanks.

on Google try: 4 pin fan controller 12v

 

[iMacConversionEnthusias]

on Google try: 4 pin fan controller 12v

Great, thank you.

 

[csdesign3]

Great, thank you.

That particular fan tends to be on noisy side and dont take much air! Have you look to the blower fan that originally is placed on left side of imac? That fan can provide a lot of fresh air and its very quite at 30%/40% of speed...

 

[iMacConversionEnthusias]

I kept the 3 fans and will definitely have a look at it. Thanks.

 

[iMacConversionEnthusias]

That particular fan tends to be on noisy side and dont take much air! Have you look to the blower fan that originally is placed on left side of imac? That fan can provide a lot of fresh air and its very quite at 30%/40% of speed...

I kept the 3 fans and will definitely have a look at it. Thanks. Sorry for posting a new message instead of a reply earlier. Now I can't find a way to delete it.

 

[iMacConversionEnthusias]

During the today lauch time, i tested the 12 6Amp porwer brick and dont work like we expected (the power brick complete turns off the led and dont provide power). I have to decide the way to go (Original PSU or 8Amp power brick). I dont like the ideia to add a push pull button, i prefer to keep the stand button to turn Chinese controller... @SubDriver @iMacConversionEnthusias

In the mean time, i have complete the holes at the back for the DP, HDMI and USB Upstream Ports, i like the way it ends

I need to buy a Headset jack that cutoff speakers when connect the audio jack, and design/print a part to secure the 4 USB ports at back inside...

I got similar result with the 6A as I posted in an earlier message. I don't have enough knowledge and experience with the original PSU. I would have definitely tried to use it if I did not cut some of the wires like a barbarian when I was dismantling the iMac. I have seen it on YouTube I think, people use the original iMac power button soldered to the Chinese little keyboard. Also are you planning to have the little Chinese keyboard accessible.

 

[iMacConversionEnthusias]

That particular fan tends to be on noisy side and dont take much air! Have you look to the blower fan that originally is placed on left side of imac? That fan can provide a lot of fresh air and its very quite at 30%/40% of speed...

That particular fan tends to be on noisy side and dont take much air! Have you look to the blower fan that originally is placed on left side of imac? That fan can provide a lot of fresh air and its very quite at 30%/40% of speed...

Sorry for the silly question but do you mean on the left side of the iMac when we face the screen and not the back of the iMac?

 

[csdesign3]

Sorry for the silly question but do you mean on the left side of the iMac when we face the screen and not the back of the iMac?

The "left fan" of iMac is the fan that blows air to the PSU and Inverter, i think its the biggesst fan inside the imac 2011

 

[iMacConversionEnthusias]

The "left fan" of iMac is the fan that blows air to the PSU and Inverter, i think its the biggesst fan inside the imac 2011

Got it. Thanks. I measured today the temperature inside the box with my setup and it went up to 45C probably at the inverter's elements it is 50-52C. I know it is not too high, but I think it would be a good idea to have a cooling fan blowing at the inverter and the Chinese board.

 

[PaulD-UK]

Later (2012+) iMacs have fan connections Vcc Gnd Speed PWM.
NOTE: the first two, Vcc and Gnd, are REVERSED compared to standard PC PWM fan controllers.

Just connecting Vcc and Gnd should turn the fan. 12v gives max speed.
It should run at lower speed with 5v or a bit less.

But speed control works best with a 4 wire PWM controller.

The read Speed wire and the PWM wire (up to 5v) should only be attached to the 4 wire PWM speed controller.

 

[csdesign3]

Hi Guys, my idea to take 5V from the BLO wire to power the step-down module did not work for me either. Not sure why.... But I got very good result (seen on the first image) by taking the power directly from the 12V power supply before the Chinese board is even powered. I do not use the PWM module as I am still waiting for it to be delivered. So here is the setup :

Chinese board - the model with the DP port.
External (Brick) power supply 8A
Original iMac inverter
Step down module powered from the 12V down to 3.3V going to the BLO of the original iMac inverter
PWM from the Chinese board directly to the PWM of the iMac inverter
Google Chrome Cast with Google TV plugged in the HDMI of the Chinese board (GCCwGTV)

I am doing all of these because the brightness of the Chinese board is not good enough and when I use the original iMac inverter the brightness improves a lot, but the inverter starts going very hot and I am afraid it won't last. Now it is still going hot but probably about half as bad as it was before the step-down module. So, I think the step-down module is definitely fulfilling its purpose. My external power supply is still getting hot which is weird because as shown on the second picture the current drawn is not near the 8A - it is below 1A.

The reason I decided to power the step-down module not from the Chinese board but directly from the 12V of the power supply is so that I do not load the Chinese board with additional power consumption it is not designed for.

Currently when I switch off the GCCwGTV the screen shows no image of course but it is clear that the screen backlight is still on. So, I have an idea to switch on/off the screen backlight either internally inside the iMac box with a little board with a small remote (I have purchased one already) or directly at the 220V with a smart WIFI socket and a smart WIFI button which I am using for various other automations around the house already. There are other solutions for the backlight on/off issue too, but I am not there yet to think about it.

I am starting to like the idea to install a small fan near the original iMac inverter inside the iMac box and control it automatically with a thermostat board inside the iMac box but will get to it later in the process.

Have a nice day guys.

Got it. Thanks. I measured today the temperature inside the box with my setup and it went up to 45C probably at the inverter's elements it is 50-52C. I know it is not too high, but I think it would be a good idea to have a cooling fan blowing at the inverter and the Chinese board.

Please do. Below are the links for diagrams etc.

https://forums.macrumors.com/threads/2009-2011-27-imac-as-an-external-display.2378570/post-31917646

https://forums.macrumors.com/threads/2009-2011-27-imac-as-an-external-display.2378570/post-31919922

@Nguyen Duc Hieu
iSight Camera conversion into usb iMac 2011 27", sorry for the bad quality but this is old photos and they are not intended to document anything at the time (just for quick guide).


i have posted photos of sdcard in another post

 

[SubDriver]

Hi, can somebody tell me how to wire the original HDD fan. I measured it and it seems to be good then I tried to connect it to 5V and to 12V with various combinations of suppling the V to the 4 wires. By the little I can see at the board behind the sticker I saw that the most right wire is VCC and the one to the left is GND and that's how much I could see. I read that 2 of the wires are for regulating the speed so I was thinking that if I short circuit them (the 2 most left wires) and supply the V to the VCC and to the GND wires it should work but it did not. Thanks.

For my 2011 A1312 iMac, from right to left the connections are VCC, GND, RPM sensing, and PWM. Here is a picture I took of my HDD fan. You can make out VCC and GND for the 2 pins on the right. And the "M" for the PWM is also visible in the shadow for the pin on the far left. By default, that leaves the sensing connection as the remaining pin.

Also, here is a picture for how I placed a small fan above the left speaker to blow air up through the inverter and power supply on my conversion. I just completed this yesterday so I can't really tell you how much of a difference it is making as I haven't used it yet, but the fan definitely puts out a lot of air at high speed. I purchased 2 fans because they were cheap. This fan is also very quiet - I cannot even hear even a slight hint of noise until it gets above around 3000 rpm.

Additionally, you can see the PWM fan control board I purchased (to the right of the fan). It is only driving the one fan for now. I am going to see how the fan works by itself before deciding if I want to connect a second small fan for the inverter and power supply or if I want to connect the HDD fan to it.

 

[SubDriver]

During the today lauch time, i tested the 12 6Amp porwer brick and dont work like we expected (the power brick complete turns off the led and dont provide power). I have to decide the way to go (Original PSU or 8Amp power brick). I dont like the ideia to add a push pull button, i prefer to keep the stand button to turn Chinese controller... @SubDriver @iMacConversionEnthusias

In the mean time, i have complete the holes at the back for the DP, HDMI and USB Upstream Ports, i like the way it ends

I need to buy a Headset jack that cutoff speakers when connect the audio jack, and design/print a part to secure the 4 USB ports at back inside...

Nice job with the ports! I may try something similar with mine in the future, but not right now.

Regarding the power supply, if you have access to an original PSU, I highly recommend you give it a shot. Although it is large and takes up a lot of space, it provides a significant amount of flexibility due to having numerous 12V power lines.

My final layout is shown in the images below. I haven't yet connected the audio to the crossovers (waiting on my small amplifier to arrive). Also, I haven't converted the SD card reader yet. I will complete both of those within the next couple of weeks.

The pictures below show the following:
1. Overall layout with everything installed in the iMac shell
2. Picture of the power button
3. Picture of the brightness control buttons
4. Picture of the brightness control button wires soldered to the PWM signal generator board (not great soldering, but it works!).
5. Short video showing the brightness control buttons changing the duty cycle of the PWM signal

 

[iMacConversionEnthusias]

Nice job with the ports! I may try something similar with mine in the future, but not right now.

Regarding the power supply, if you have access to an original PSU, I highly recommend you give it a shot. Although it is large and takes up a lot of space, it provides a significant amount of flexibility due to having numerous 12V power lines.

My final layout is shown in the images below. I haven't yet connected the audio to the crossovers (waiting on my small amplifier to arrive). Also, I haven't converted the SD card reader yet. I will complete both of those within the next couple of weeks.

The pictures below show the following:
1. Overall layout with everything installed in the iMac shell
2. Picture of the power button
3. Picture of the brightness control buttons
4. Picture of the brightness control button wires soldered to the PWM signal generator board (not great soldering, but it works!).
5. Short video showing the brightness control buttons changing the duty cycle of the PWM signal

View attachment 2476644
View attachment 2476645
View attachment 2476646
View attachment 2476647


View attachment 2476648

Very nice build, neat and tidy. Where did you get the buttons from.

 

[csdesign3]

For my 2011 A1312 iMac, from right to left the connections are VCC, GND, RPM sensing, and PWM. Here is a picture I took of my HDD fan. You can make out VCC and GND for the 2 pins on the right. And the "M" for the PWM is also visible in the shadow for the pin on the far left. By default, that leaves the sensing connection as the remaining pin.

Also, here is a picture for how I placed a small fan above the left speaker to blow air up through the inverter and power supply on my conversion. I just completed this yesterday so I can't really tell you how much of a difference it is making as I haven't used it yet, but the fan definitely puts out a lot of air at high speed. I purchased 2 fans because they were cheap. This fan is also very quiet - I cannot even hear even a slight hint of noise until it gets above around 3000 rpm.

Additionally, you can see the PWM fan control board I purchased (to the right of the fan). It is only driving the one fan for now. I am going to see how the fan works by itself before deciding if I want to connect a second small fan for the inverter and power supply or if I want to connect the HDD fan to it.
View attachment 2476608
View attachment 2476609

With that crossovers on speakers can you ear them working? Where did you buy them?

 

[SubDriver]

Very nice build, neat and tidy. Where did you get the buttons from.

From Amazon. The power button is a latching style button and the brightness buttons are momentary. Here is a link to the brightness buttons. Here is a link to the power button.

 

[SubDriver]

With that crossovers on speakers can you ear them working? Where did you buy them?

I got them from amazon. I haven’t tested yet. I am waiting for a small audio amplifier to arrive. The audio feed from my LCD driver board is too weak.

 

[Nguyen Duc Hieu]

PWM fan controller board.
This small board can control 3 fans and have a thermal sensor.

12V PWM PC CPU Fan Temperature Control Speed Controller Module High-Temp Alarm | eBay

Support all within 12V 5A fans, synchronous rectifier output, high efficiency! It can be opened with a three-wire fan monitoring function (stall warning). TFL (No. 1): The lowest temperature channel PWM setting, when ON state FAN1 PWM minimum is 40%, when OFF the minimum PWM of FAN1 is 20%.

www.ebay.com

This board offer manual knob control, only 2 pins of the fan is connected.

3V~35V 12V 24V 5A PWM DC Motor Speed Controller Adjustable Switch LED Fan Dimmer | eBay

PWM Duty Cycle: 1% -100%. PWM Frequency: 10khz. Max Output current: 5A. We afford all cost if it's our fault. We maintain the excellent service standards.

www.ebay.com

You will need 3 connector cables as well, a little pricey and I don't know why...
Or you can cut them from a PC junk yard if you can find one.
Of course some wire tester, soldering will be required as well.

6pcs 4 Pin 26cm PWM Fan Extension Power Cable Connector Case Male to Female for | eBay

The cable is a 4-pin female connector to a 4-pin male connector, suitable for CPU and PC case fans. Black sleeved nylon braided cable, more durable and make the inside of pc case looks more clean & tidy.

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3 Pcs Computer Power Cable Fan Splitter Adapter for Cooling | eBay

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[Maccam1]

I am converting a 2010 Imac 27" monitor and have been following your posts. Thanks, great work.

On the power button, has anyone tried a converter board to "convert" the momentary power button to a latching button. I was thinking with the right board the fan could also be connected. I was looking at this board from Pololu, Mini Pushbutton Power Switch with Reverse Voltage Protection, LV

 

[csdesign3]

I am converting a 2010 Imac 27" monitor and have been following your posts. Thanks, great work.

On the power button, has anyone tried a converter board to "convert" the momentary power button to a latching button. I was thinking with the right board the fan could also be connected. I was looking at this board from Pololu, Mini Pushbutton Power Switch with Reverse Voltage Protection, LV

I think this button may fit in the place of the existing power button... This is a persistent on or off... I will buy to test

2,67€ | KAN-28 Flashlight Switch Self-Locking SMD/Inline Push Button Power Switch Switch Accessories

2,67€ | KAN-28 Flashlight Switch Self-Locking SMD/Inline Push Button Power Switch Switch Accessories

a.aliexpress.com

 

[Maccam1]

I think this button may fit in the place of the existing power button... This is a persistent on or off... I will buy to test

2,67€ | KAN-28 Flashlight Switch Self-Locking SMD/Inline Push Button Power Switch Switch Accessories

2,67€ | KAN-28 Flashlight Switch Self-Locking SMD/Inline Push Button Power Switch Switch Accessories

a.aliexpress.com

I wanted to keep the look and use of the iMac Power Button, so making it persistent was my goal. The price of this at $4USD is pretty good, although the shipping is high.

 

[csdesign3]

I wanted to keep the look and use of the iMac Power Button, so making it persistent was my goal. The price of this at $4USD is pretty good, although the shipping is high.

You can keep the look like I want to, internally remove the left speaker and you will see the original press button, use an air dryer to release the glue, after that you can remove the press button and replace with the button I've suggested.. I think they fit with a small a small modification

 

[SubDriver]

I am converting a 2010 Imac 27" monitor and have been following your posts. Thanks, great work.

On the power button, has anyone tried a converter board to "convert" the momentary power button to a latching button. I was thinking with the right board the fan could also be connected. I was looking at this board from Pololu, Mini Pushbutton Power Switch with Reverse Voltage Protection, LV

I hadn’t thought of something like this. Seems like it would work as long as you have the skills and tools to solder something that small. The output of the board would need to connect to pins 6 & 7 of the iMac PSU.