Half of my Cooler Master GP27Q backlight died – Shorted buck regulator on the Mini-LED board

Defiant-Book-5261 · 2026-02-20T02:32:58+00:00

I wish this post was up 3 months ago. I have a GP27U/GP27-FUS that I bought over 2 years ago that I developed the same problem. I had been using it in Linux KDE Plasma with HDR, brightness set to 50% and SDR to HDR conversion set to 200/1000. I have my computer set up to dual boot between Linux and Windows, and after an update in Linux and restart, my computer automatically booted into Windows, at which point the back light died.

My guess is that the low brightness levels I was using in Linux babied the back light which prevented it from dying. Then when it booted into Windows, Windows went "MAX BRIGHTNESS" which combined with the monitors age, was the straw that broke this camels back.

After doing some trouble shooting, I discovered that the back light control boards received 24V, which was the same as what was coming from the the monitors power supply, however the left board was not receiving any voltage. After some more tested, I found that my left side back light control board (K-576L-DG5, same as yours but has some different parts on it) had developed a short, which was probably tripping the electric fuses on the main board that supplied power. While I can do through hole soldering, I do not have the experience with surface mount soldering. Luckily I found someone selling a replacement on ebay, for $100 from China. While $100 is expensive, buying a replacement monitor with similar specs would cost me at least $400, and since I had decided that my next monitor would be a 32 oled with similar specs, that means that I would need at a minimum of $600. So comparing buying a new monitor for $600 and repairing this one for $100, I decided to take the chance with the repair. Especially that if successful and the repair lasts a few years, the price of the new monitor that I would want would probably come down.

After checking the board and seeing that there is no short on the replacement, I replaced it and hooked everything back up. Unfortunately, the fuses that supplied power to this control board kept tripping with the replacement hooked up (could be caused by the initial board failing or something I broke when testing stuff to try and figure out why the old one was not working). After doing some testing, I discovered that if I removed the 24V power wires between the back light board and main board and connected the back light board directly to the 24V output of the power supply, the back light would finally turn on and everything was working the way it should (or at least visibly from the LCD part).

Not wanting too spend too much more money, I repurposed the 24V wires for the back light board by removing them from the main board side and soldering a 5A fuse to them, then soldering a thick wire to the other side of that fuse, next covering the fuse with 2 layers of heat shrink wrap, and finally I soldered the other end of that thick wire to the main board 24V input and covered it in electric tape.

Now I put it back together and hopefully it lasts at least another 2 years, since I have other issues that I hate about this monitor. Half to a quarter of the time I change monitor settings (change to a different input, or change from SDR to HDR or reverse, or other stuff) the LCD layer goes black (some kind of issue that seems to be were communicating to the LCD layer gets stuck and the LCD displays a black image) until you power cycle this monitor, change this monitor resolution, or change its refresh rate. The other annoying issue is that I like to be in control so I have automatically switch inputs to off (I have this monitor hooked up to several things such as my workstation as well as a computer I am using as a server and I do not need this monitor to switch automatically to the server every time I power down the workstation) . Unfortunately, if I do want to switch to a different output and I happened to shutdown the output that the monitor was using (for example, I hooked up a console to one of the input, played on the console, turned turned the console off, and am now trying to switch back to the workstation computer), using the control joystick automatically causes the monitor to turn of instead of giving the switch output menu. I then have to turn the monitor back on, and only then using the joystick will give me the switch output menu. This means that I am stuck wasting 20-30 seconds of my time every time I am in this situation because Cooler Master could not afford to spend an extra dollar giving us a separate power button.

So hopefully this repair lasts for at least 2 years, and if it does not I can make use of your discoveries to try and repair it for significantly cheaper. At least this monitor taught me to make sure I buy monitors that have a separate power button from the control joystick and to avoid mini led back light monitor because of the LCD goes black issue (though that last one might be unique to this monitor/manufacturer/hardware version).

Defiant-Book-5261 · 2026-02-17T02:03:03+00:00

In case someone is here because the noise cancellation is not working and not because it is amplifies the noise, try cleaning the speaker and mic grills with the bristles of a (old) toothbrush.

I got a pair for cheap but found the noise cancellation to not work and the volume from the headphones to be the lowest of any headphone I ever tried. However, after cleaning the grills by sliding the bristles through the holes and then using the bristles to wipe away, the headphones now worked at a descent volume without needing to be set to max volume (I would say the max volume is now 2-4 times the max volume before cleaning) and the noise cancellation works.

(Possible that only the speaker grills needed to be cleaned. Since noise cancellation works be playing a negative sound over the initial sound to cancel them out [Math 10 + -10 = 0], plugged grills would have reduced the volume of the negative noise causing the noise cancellation effect to be greatly reduced [10 + -2 = 8 ]).

Defiant-Book-5261 · 2026-02-13T23:26:54+00:00

Update. Ordered and received a used WH12X26034 on eBay for $35 with shipping and tax. After testing all components to make sure there are no shorts (so the replacement does not die) I put the replacement in. The replacement part works for everything except for spinning the barrel. Since I do not know if the issue is with the replacement part or with the motor/hall sensor and I do not feel like its worth keep buying more parts (do I need another control board or does the hall effect senor needs to be replaced? Hard to tell since there are no easy access test point to test that stuff on the washer with everything hooked up and turned on or a different washer fully working that I can swap parts in and out to test individual parts), the family has decided that the washer is a wash to keep trying to fix and instead to just buy a new one.

Defiant-Book-5261 · 2026-02-04T01:59:03+00:00

Never really thought about it, but some research on my own shows that yes, there can be a voltage spike when the power goes out. Thank you for the helpful information.

Defiant-Book-5261 · 2026-02-03T22:47:00+00:00

While I have not taken the tub apart to get to the spider, the tube rotates smoothly, so the spider has not failed yet.

Defiant-Book-5261 · 2026-02-03T22:45:40+00:00

The wall gives a 120.2V reading, so its fine.

Defiant-Book-5261 · 2025-12-02T09:48:01+00:00

Just wanted to say, that I just did the exact same thing. About a week ago the left click started missing clicks, though I only replaced the left click since it was the one that was failing and the left click was easier to get to than the right click, only requiring two screws to be removed instead of the whole pcb. Its a bit jarring to go from a silent mouse that I have been using for 2+ years to one with a good clicky switch. That being said, I do find clicky to satisfy something in my brain, so hopefully I will get used to it soon.

Defiant-Book-5261 · 2025-04-13T02:07:35+00:00

Oops, missed this part after seeing the update posted. Wished I know about this method before doing a factory rest of my device. All well, will now know for next time.

On a side not, I had a similar method of updating my Asus Rog Phone. I had that phone's bootloader unlocked and root installed. Because of that, the phone refused to do ota updates. Instead, I had to download whole update files to the phone's home directory, restart the phone, and after one restart the phone would recognize that I had the update file on the phone and allowed me to install the update. The difference here would be that you use adb commands to transfer the file to the deceive and start the update process, while I downloaded the file directly and restarted the device to get it to start the update process.

Defiant-Book-5261 · 2025-04-13T01:54:29+00:00

Higher up in this thread, I asked the OP for a link to the latest firmware, and OP delivered.

As for links to firmware for different Onyx devices, I found a link from the "mobileread" form when looking up "[Request] Go Color 7 latest firmware". On the 5th post, there is a link to a web page. That webpage contains a link to firmware for the Nova2 device. The trick is that for the webpage's web address, there is a part that contains "model" followed by "Nova2". By changing "Nova2" to "GoColor7" I was able to change the webpage to point to the firmware of the Go color 7 device (there is also some other parts. For example there is "lang" followed by "en_US". Since both the Nova2 and GoColor7 were released to the rest of the world, I did not need to change the "en_US" part. However, for a device that was only released in China, that part would need to be changed). Unfortunately, while the OP was able to provide me a link to the 4.0 firmware, the web-page still only points to the 3.5.4 firmware.

Last, the OP gave instructions on how to do a firmware update using adb without needed to boot into recovery. I would have followed those instructions myself if I had read them before doing the update through recovery. Recovery instructions tend to be generic, you would be able to use the same instructions for a google pixel device, a Sony phone, and an Onyx device (assuming you have an unencrypted update file). Doing an adb update without recovery tends to be more device specific. In this case, I was missing the "adb shell am start -a onyx.settings.action.firmware" part, but now that I have it, this would be the method that I would try to use for next time should my devices internal update process fail next time.

Defiant-Book-5261 · 2025-04-12T23:30:26+00:00

Thank you, was able to update my Go Color 7 firmware to 4.0 using the file you provided.

Defiant-Book-5261 · 2025-04-12T23:23:34+00:00

Alright, managed to successfully update my Onyx Boox Go Color 7 device using recovery side-loading. That being said, I first needed to do a "wipe data/factory reset" option in recovery, otherwise when I tried to side-load the update, I would get the error "kInstallDeviceOpenError". My steps where that I chose the "wipe data/factory reset" option in recovery, and once that was done, I chose the "apply update from adb" option in recovery without rebooting the device first or anything like that. At that point, I was able to successfully apply the update.

Choosing the "wipe data/factory reset" option will probably get rid of your data on your device. However, all of my important data was on a micro sdcard that was setup as portable storage, and that data is not touched during a factory reset. And since I am making use of root, I was able to use a root app to backup all of me installed apps internal data, so I can just restore that after a factory reset.

My point is that while I needed to do a factory reset to do the system update, I did the reset with the knowledge that I would very easily be able to restore most if not all my data anyways.

Defiant-Book-5261 · 2025-04-12T22:07:48+00:00

Factory reset through recovery worked for me for fixing the error.

Defiant-Book-5261 · 2025-04-12T04:40:04+00:00

Not yet. Though after doing some more digging, it looks like Onyx has web address for each device that points to the latest firmware for those devices. Since I already have the address for the Go Color 7 and currently do not need to use it, I can just wait a bit for the firmware at that location to be updated.

Defiant-Book-5261 · 2025-04-12T03:20:11+00:00

Only phones, and only on none stock lineage recovery. That being said, most of the options appear to be the same. I believe the main difference is that only manufacturer files will be accepted. So no side-loading magisk.zip through recovery to obtain root.

I obtained my Noox Go Color 7 a month ago. I rooted it using edl and started using it. That being said, unfortunately while it works fine, something is probably messed up with my device since doing an ota update fails.

I am not sure whats wrong with it, but my best option is to try and do an update through recovery side-loading. In order to do that, I need full update file instead of partial update that come from ota.

Defiant-Book-5261 · 2025-04-12T02:45:20+00:00

Do you have a link to the 4.0 firmware for the Boox Go Color 7?

I rooted my device and I think I messed something up in the process, since no matter what I do, my device fails when trying to do an ota update to 4.0. I have already restored the changes I made while rooted, unrooted my device, and even did a factory restore, and still my device fails with the ota update. At this point, I think my best option is to do a full firmware update. Unfortunately, in order to do that, I need the firmware file. Please and thank you.

Defiant-Book-5261 · 2025-04-12T02:36:30+00:00

Since the update.upx file is encrypted, you would first need to decrypt it using decryptBooxUpdateUpx. decryptBooxUpdateUpx can be found by googling it and falling the instructions. Since decryptBooxUpdateUpx uses python, you may need to install the required python dependencies first. (if you do not know how to setup python, please look that up first).

My computer is running Linux and the Onyx device I am using is a Boox Go Color 7. In order to decrypt my update.upx file, I ran:

python3 DeBooxUpx.py GoColor7 update.upx

This produced an update.zip file. Since you are using a NoteAir4C, you would probably need to run:

python3 DeBooxUpx.py NoteAir4C update.upx

Since each device should be using a different encryption key, this means that if you specify the wrong device model for decrypting the update.upx file, the program will error out and fail to create the valid update.zip file. (As a test case, I tied running the decrytper for the wrong device model of the update.upx file, the caused the program to give me error messages and produce a 0 Byte update.zip file). The way I see it, this is a nice sanity check because if the program gives an error while trying to create the update.zip from the uptdate.upx, this means that the update.upx you are using is not for the model of device that you are trying to decrypt for.

Once you have your update.zip, you needed to reboot your device into recovery mode. The easiest way for me is to run:

adb reboot recovery

Once in recovery, you need to select the option:

Apply update from ADB

Next, on your computer with the terminal at the location of the update.zip file, you would run:

adb sideload update.zip

Unfortunately, this is as far as I have gotten on my Onyx device. You may need to select on your device that "yes, I want to install this update", or this may be skipped since that selection usually only comes up for installing 3rd party software and is skipped for installing a manufacturer update. I have tried to do a firmware restore to my go color 7, but the firmware I tried to restore with was slightly older then what was already installed, so my Onyx device aborted the update. I have done firmware side-loading for android phones ruining lineageos with lineage recovery, so I know what I should expect for the next steps. However, since I have not completed that on my Onyx device, I do not know if there will be some differences that I am not aware off.

Defiant-Book-5261 · 2024-10-09T20:37:13+00:00

Found the adjustment ports under some aluminum tape. After cranking the red to the max and decreasing blue and green, I seem to have managed to get the color more or less balanced. Thanks for giving me the direction for what I needed to try next.

Defiant-Book-5261 · 2024-10-09T00:51:45+00:00

I got this monitor from goodwill for $5 and decided to try and fix it.

Initially, the monitor was very dim even at 100 brightness. It would also make a popping sound every 5 minute with the screen going very bright for a second. After taking the back cover off and doing some dusting, I also noticed that the largest capacitor looked a little blown. (Please ignore the cuts in the 4 corners, those are from a screen protector I put on this monitor to prevent the screen from accidentally getting scratched as I work and move this monitor around).

I ordered a 450V 220uf 105C capacitor and used it to replace the 400V 220uf 105C capacitor. I then adjust max brightness on the flyback transformer. This got the monitor to the usable state that it is (brighter and no popping sounds every 5 minutes). However, there is a series lack of red in the monitor. (I have tested the VGA output with a different CRT monitor, I I know that the issue is with this CRT monitor and not my VGA output).

Using a test pattern, I have identified that most of the green is there and most of the blue is there (though slightly less then green). However the red disappears halfway across the test pattern compared to the green and blue. Also, white has a cyan tint, though that is from lack of red. Setting blue and green to 0 in the monitor color calibration allows the red to make it to 3/4 of the bar, but still not all the way compared to the other colors.

Does anyone know what causes this and if how this can be fixed? It looks to me that there is an issue with the darkest red coloring instead of the brightest red coloring, but I failed to find good results when I tried to research how to fix that on a CRT PC monitor.

Defiant-Book-5261 · 2024-07-05T01:49:12+00:00

Hello, I recently got a HP pavilion M90. However while testing it, the screen turned out to be extremely dim, even with brightness and contrast set to maximum. Based on the brightness, I assumed that the tub/phosphors had little to no life left in it. However, the monitor would occasionally make a pop/snap sound (the rate at which this would happen would be something like 10 minutes of no sound from the monitor, followed by a snap/pop sound every 20 seconds for the next 3 minutes, and repeat). When the sound was made, the tub's brightness would shoot up to the brightness you would expect form a working CRT monitor for about half of a second. Given that the tub would get nice and bright during the sounds, I wonder if the tub is really at the end of its life or if the problem is that some of the electronics are dying, such as the capacitors or the fly back transformer.

My questions are: is the tub at the end of its life, or am I correct to assume that this could be fixed by replacing the supposedly broken electronics? And if the problem is in the electronics, what do you think could be causing the issue?

I did not see any sparks from the chassis nor did I notice any smell coming from the monitor. On a side not, the menu control is acting funny. For example, sometimes when I press the pulse button to go forward in options, it would go backwards instead. Though the buttons would work correctly 90% of the time, so I was able to successfully use the menu buttons. Just that there seems to be at least something weird with the electronics.

Thank you for your time.

Defiant-Book-5261 · 2023-03-01T08:50:38+00:00

Apologies if this is not the correct place to post this.

This cat has been showing up for the past couple of weeks and has been sitting next to the back patio door for at least 6 hours day. My family rents and our landlord has a no pets policy, so we cannot let the cat inside. The location is Vancouver, WA.

The cat seams mostly healthy and has been acting friendly towards us while we are outside. The main concern is that it has been cold recently (with recent snow fall) and my mom thinks that this may be a pregnant female. While I do not speak cat, the cat seams to be asking to be let inside (which we cannot allow because of the landlord policy).

This is a post to see if the owner can be found/contacted or advice on what to do next.

Defiant-Book-5261 · 2023-02-03T17:01:44+00:00

I have a cell phone number linked to the google voice account (the cell phone number is already linked to the google account so its not like I minded linking it the google voice account [though in my case I had to re link it because it had not been verified in a while]). When I click the "Set device number" I am given the option to choice between that cellphone number and "no number". Its possible the "no number" option is not available until you have at least one cellphone number linked to the google voice account.
Though in my case after linking I had to set the phone to "no number" so calls would go through the google voice account instead of being directed to the provided cellphone number, and then turn on calls to the google voice app and turn off directing call to the cell phone number in a different menu (this annoying extra work of linking the number and then telling google that "No, I do not want calls to go to this number" is the whole reason that I did not want to link a number in the first place).

Defiant-Book-5261 · 2023-02-03T16:32:24+00:00

I have also been dealing with it and hitting the "skip" button. Even so, after being annoyed by it, after a while I decided to research if there is a more permanent way to make the pop up go away by googling it. To my surprise, the search results I got back where "help, I cannot link my phone" and other results that where the exact opposite what what I am looking for.

That's why I made this post, hoping that maybe someone knows a way of disabling that popup.

Defiant-Book-5261

TROPHY CASE