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DIY 5k Monitor - success :-)
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All switched power supplies will produce some form of sound when converting AC to DC. Some produce more, some produce less. It's perfectly normal.Question again about the iMac PSUs.
Does anyone else experience the same noises while powering the boards from the PSU itself?
I blamed that the Delta was making this noise due to to the faulty repair that I made.
But just in case I bought another one that was tested by the seller and it was claimed as fully operational.
This time LITEON PA-1311-2A2
Yet, even under 30W load it’s making a considerably loud noise. As if it was overloaded.
Here’s the noise recording:
IMG_2124.MOV
drive.google.com
Any ideas why or how to overcome this?
By the video you sent us, I would say you wont hear this sound once you put the panel back on. It sounds like a rather easy to block sound.
Yes, I guess you’re right.
I sent both to a local shop. They say it’s a common noise coming from the diodes.
And that it’s normal, not a sign of stress.
I’ll give it a try for a day to see how it sounds with the display installed.
Although, the built-in MEMS mic is going crazy (I guess Apple would do some sound filtering)
Mic recording
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Good tips, thanks!
The noise appears at any considerable load. Either when the display goes up. Or the device is charged via USB-C. Surely when both.
Just tried the DP cable – same result.
Overall, I can hear some squeaking noise from an assembled display when it's very quiet. I'll see if I can used to it and if it's stable at all (I'm morally prepared to hear a blow one day).
Just if it helps anyone. The 2020 display has a different mounting point for the FaceTime camera, from the one described in the Aiwi guide. (Or at least from what I realised from the guide)
The mount is an integral part of the display, so it’s a bit trickier to mount an external camera which will surely be thicker than the original one.
I had about 1 mm hole between the case and the display using the same camera as Aiwi.
Attaching some pictures.
Personally, I’m not happy with the camera sensor, especially at the low light. So I tend to keep my assembly without it.
The mount is an integral part of the display, so it’s a bit trickier to mount an external camera which will surely be thicker than the original one.
I had about 1 mm hole between the case and the display using the same camera as Aiwi.
Attaching some pictures.
Personally, I’m not happy with the camera sensor, especially at the low light. So I tend to keep my assembly without it.
Attachments
Yup, 2560x1440@240Hz via setting a custom resolution in NVIDIA control panel. I was surprised too. Not sure what else to say other than it works.
Right. I believe you are mistaken.
You are feeding the display driver board with a 2560x1440@240Hz signal, but the panel itself will only show 60Hz.
For the sake of being thorough I repeated your process:
As you correctly state, one is able to set a custom resolution in the Nvidia Control Panel. Here I have set it to 4K 144Hz.
The iMac panel works just fine, but once compared to the real 144Hz 4K display it's obvious that the iMac panel is really just refreshing at 60Hz. You can see this by just dragging the cursor around on the wallpaper.
Noise on (switch mode) power supply are mostly from the transformers, caused by vibration of harmonic frequencies.Question again about the iMac PSUs.
Does anyone else experience the same noises while powering the boards from the PSU itself?
I blamed that the Delta was making this noise due to to the faulty repair that I made.
But just in case I bought another one that was tested by the seller and it was claimed as fully operational.
This time LITEON PA-1311-2A2
Yet, even under 30W load it’s making a considerably loud noise. As if it was overloaded.
Here’s the noise recording:
IMG_2124.MOV
Any ideas why or how to overcome this?
If it's disturbing, what you can try is: when switched off, apply (more) tape to the transformers. This increases the mass so that the resonance frequency changes, and secondly it might also dampen the vibration of the transformer, so that the sound appears less.
This makes perfect sense.
This panel is IPS, Panel TypeOxide TFT-LCD, LCM. Response Time14/12 (Typ.)(Tr/Td). Right?
With a frame rate at 60Hz.
Chief Blur Buster, the author of TestUFO, made a comment that is relevant here, I believe
5k iMac screen at 60Hz
Remember the old CRT monitors? They could increase the frame rate as the resolution was lowered. Because they had a bandwidth limit in MHz. But modern screens are not analog, so can't just perform that kind of adjustments.
Attached are photos of my final alternative to using iMac adhesive strips. Using an iFixit pizza cutter, spending an hour cleaning off adhesive, and spending another $20 for more tape is not my idea of a good time. For this project, I used stuff I had laying around. I don't even know what the adjustable, elastic silicone strap is called (I use them for cable ties), but I attached one end to the top of the metal glass display frame with a zip tie. The other end passes through the cut-out apple logo "stem" and is held in place via tension using a small rubber rod. Excess strap is tucked back inside the housing. The slight tension pulls the glass towards the housing; gravity holds the glass in place on the bottom. There is no danger of the glass falling (even at extreme angles) and there are no light leaks.
If I need to work on the display, I can slide the rod out, give the strap some slack, tip the display, then reinsert the rod where needed to achieve the correct angle to access the monitor innards. I put a little masking tape on the bottom of the display if I get nervous!
The purple "screen" on the apple logo is a piece of leftover plastic from the bottom of an old MacBook case. It provides extra ventilation.
If I need to work on the display, I can slide the rod out, give the strap some slack, tip the display, then reinsert the rod where needed to achieve the correct angle to access the monitor innards. I put a little masking tape on the bottom of the display if I get nervous!
The purple "screen" on the apple logo is a piece of leftover plastic from the bottom of an old MacBook case. It provides extra ventilation.
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Just for an update on the T18 boards... I have now been using mine on a mix of 12v caravan power and 240V/19v plug pack as I travel around Australia and it is FLIPPING AWESOME.
So glad I did this conversion and this board has handled being shuffled around the caravan with dubious quality power inputs and plenty of bouncing up and down on corrugated roads and it is flawless still.
So glad I did this conversion and this board has handled being shuffled around the caravan with dubious quality power inputs and plenty of bouncing up and down on corrugated roads and it is flawless still.
I have also been considering alternative to the iFixIt tape, even though I purchased two sets.
One option could be using neodymium magnets. They come in different shape and sizes.
Neodymium magnets
Where there are WiFi and BT antenna it would be doable to use neodymium magnets.
But the left side of the screen has only a small glass margin, and the back case is very slim, so I gave up on that idea.
The 2011 iMac also has metal strengthening attached to the screen, as well as to the case.
As the glass edge of the screen panel is so thin I wonder if that is essential?
But I originally bought a pack of miniature magnets, so I may return to the idea at some time...?
But the left side of the screen has only a small glass margin, and the back case is very slim, so I gave up on that idea.
The 2011 iMac also has metal strengthening attached to the screen, as well as to the case.
As the glass edge of the screen panel is so thin I wonder if that is essential?
But I originally bought a pack of miniature magnets, so I may return to the idea at some time...?
So if anyone else will ever wonder: indeed, the iMac PSU cannot be heard really in day-to-day when the monitor is assembled.
All this noise is blocked quite nicely.
However, it is still picked up by the mics inside.
I'll play with the tape as @USB3foriMac suggested next time I'll be doing something inside of the iMac.
Will provide further feedback on that
I considered that, and still think that would be a good experiment. My concerns were 1) could you recess the magnets enough so there was no gap, and 2) the magnets are powerful, so they would need to be very firmly attached on both sides.
There is a thin magnetic tape with adhesive on one side that might also be worth a try. But would it be strong enough? If you come up with a good tape alternative, please let us know! It's still odd to me that the Apple engineers used double-sided tape as their final solution for the iMac. But then again, they assumed no one would be doing the stuff we're doing!
3) The risk of ending up with the panel offset to either side, however minute. Most likely scenario if magnets are used in pairs, that attach to each other
That is a good point.
I will open it up again, and have a close look. With a focus on how it can be done.
I can confirm there is 12V present on the DC_In pins closest to the eDP connector on the JRY board (when the board is supplied by a 12V supply, obviously.)
By switched I assume you mean when the JRY board is switched off but still plugged in to the power source?
In my brief test, I am still seeing 12V across these DC_In pins when the board is off (and there is no red/green LED on the control strip.) The same voltage is also present across the red alternative power connector next to the barrel plug.
I am getting a reading of 3.3V across the pins of the USB header at the corner of the JRY board next to the HDMI port. Unsure if that is a fault on my board? (I carelessly plugged in a 12V supply with reversed polarity the other day. The JRY board still seems to work, including the USB-A 2.0 ports, but there may be unseen damage.)
I do however get 5V across the IR port header pins, and also across the internal 6-pin USB header located directly next to one of the USB-A ports. As @sadontsev mentioned, the IR port remains powered at 5V when the board is off (but plugged into power). Whereas my two USB headers (3.3V at pins on corner next to HDMI, and 5.0V at pins next to USB-A port, when powered) are showing between 1.5V and 1.9V when the board is off. Unsure if this is normal.
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I can confirm the DC in pins next to the barrel will provide 12V supplied through the barrel. They are connected directly.
Regardless of the board state.
During my tests, there was no voltage on the USB pins when the board is in off state (but powered via barrel).
I ended up soldering fan controller to one of the USB A ports, so it goes off when the board is in off state.
Always goes off for me, while the connected USB accessories still work well (I have a mic and a camera connected).
By the way, have anyone figured what IR controllers are compatible with the JRY board?
I may want to use it to control the brightness. What I realised is that the MonitorControl controls the brightness on a software level. That, funnily enough, dims taken screenshots as well. And there are also bright flashes while I swipe between the open full screen apps.
A bit inconvenient for me.
Thanks for the update. Did you test the internal headers as well as the USB-A ports?
I think I may have fried something on my board...
I have just experimented with various monitor control apps and connection methods to the JRY board for DDC control.
The JRY advertises itself to the computer as DDC compatible, initially I assumed this occurred using the USB Serial connection shown in System Report. Edit: This is incorrect.
However, as @sadontsev mentions, neither the Mac hardware keyboard buttons, nor the monitor control software can change the Brightness or Contrast using DDC when the display is connected via DP or USB-C, in my experiments. (This includes connecting the JRY board via the USB-B port, which as we surmised earlier, presents the USB 2.0 hub and USB Serial to the connected computer separately to the USB-C connection.)
However, when the JRY is connected via HDMI, it appears I can control hardware Brightness and Contrast on the display using third-party software — both Lunar and BetterDisplay work — they even permit me to use the Apple keyboard brightness buttons.
Edit: it appears HDMI has two dedicated pins/lines for DDC/CI signalling using I2C data, which explains why the HDMI port accepts DDC software commands from the Mac. There is a method for sending I2C via DisplayPort Alt mode (via USB-C) but it does not appear to work with the JRY board.
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I tested the pins on the “other” side of the board and it was consistent across USB-A and USB-B ports.
However, I decided to use one of the A ports, as the purpose of it was more familiar to me
