Acer 4K monitor troubleshooting - Page 1
Forum section: electronics / repair

author: fiskmaas
author_rank: Contributor
timestamp: May 19, 2023, 10:11:29 am
content: Hey EEVblog forum,So I'm trying to diagnose what could be wrong with my monitor. It's a Acer xv273k, the problem is that it blinks black every ~500ms. Here's a video of the problem:https://imgur.com/a/UcL3sEbSo it's definitely a monitor problem, it persists on OSD and on different inputs. I'm wondering if anyone knows what it could be, or how to troubleshoot. I'm not very experienced with troubleshooting electronics like this, but I have all the gear required (cheap oscilloscope, multimeter etc.) and experience soldering.Any and all help welcome as I was hoping to get some more time out of this thing, warranty expired just 6 months agoThanks!

author: wraper
author_rank: Unknown
timestamp: May 19, 2023, 10:27:19 am
content: Seems to be a backlight issue as image seems to persist when backlight disappears. Probably protection kicking in and backlight restarting. Could be a problem with backlight driver or an issue with LED strips which causes protection to kick in. Try adjusting brightness setting and see if it changes anything.

author: n4u
author_rank: Contributor
timestamp: May 19, 2023, 10:28:25 am
content: Yea.. You may additionally check with flashlight - it should be visible image when you highlight the screen. I will start with temperature of inverter and capacitors.

author: fiskmaas
author_rank: Contributor
timestamp: May 19, 2023, 10:47:00 am
content: Thanks both for your quick answers.Quote from: wraper on May 19, 2023, 10:27:19 amYep, lowering brightness seems to fix it for the time being, going above ~60% will make the blinking start again. Does that indicate something specific?I also tried the flashlight and it seems to just be the backlight. Image is constant.

author: Traceless
author_rank: Frequent Contributor
timestamp: May 19, 2023, 11:19:22 am
content: I'm going on a hunch here and say this is a power supply problem. I've had similar issues with Samsung screens. Does the power LED go slightly dim when the backlight cuts out?

author: fiskmaas
author_rank: Contributor
timestamp: May 19, 2023, 11:31:07 am
content: Quote from: Traceless on May 19, 2023, 11:19:22 amI will check if the problem comes back. Now the problem won't come back, obviously because I'm trying to get it to come back.Another thing I could add is that it usually happens in the morning after the screen has been off for a while. Yesterday it went away after a while, and it seems to be the same today.

author: wraper
author_rank: Unknown
timestamp: May 19, 2023, 11:36:52 am
content: Quote from: fiskmaas on May 19, 2023, 11:31:07 amWhile electrolytic capacitor failures are not nearly as common like a decade ago, it's probably the issue with such symptom. When capacitor heats up, its ESR becomes lower which may cause the issue to go away when it warms up, but not for long until capacitor fails completely.

author: Traceless
author_rank: Frequent Contributor
timestamp: May 19, 2023, 11:44:21 am
content: Keep an eye on it. If this is similar to the problem I have in mind a component in your PSU is marginal and will cause the supply voltage drop under a critical threshold (which may cause the power led to dim down slightly). The feedback circuit will detect that and restart the supply. This will repeat, eventually the power supply stabilizes and stay on if you don't turn it of. In my experience the component degrades exponentially if you power off the screen and let it settle for a while. So basically what will happen is: First it flickers once and then just works. If you switch the screen off for a while and turn it back on it will flicker twice, next time ~4 times then ~8 times and so on until it will not stabilize at all any more.

author: fiskmaas
author_rank: Contributor
timestamp: May 19, 2023, 11:48:20 am
content: Quote from: wraper on May 19, 2023, 11:36:52 amHow long is that usually? Are we talking 20 minutes or could it be 3+ hours? Because yesterday it went away pretty quick (1 hour or so) but today it might have been 3-4 hours.Quote from: Traceless on May 19, 2023, 11:44:21 amOk, will check. The problem is usually pretty constant, ie. not doubling like that, just consistant ~500ms on/off.

author: Traceless
author_rank: Frequent Contributor
timestamp: May 19, 2023, 11:59:38 am
content: @fiskmaas: It might be a bit different for you since you have an Acer unit, not a Samsung. Someone documented their troubleshooting process for a faulty Samsung supply (see video below). For for those Samsung screens it is easy to diagnose because they use an external DC power adapter so you can just swap the faulty one or hook up the screen to a bench PSU. I assume your Acer has an integrated supply with IEC-cord?

author: fiskmaas
author_rank: Contributor
timestamp: May 19, 2023, 12:08:41 pm
content: Quote from: Traceless on May 19, 2023, 11:59:38 amNo it's an external PSU aswell. I don't have any PSU that's equivalent I think, but I'll check.

author: fiskmaas
author_rank: Contributor
timestamp: May 19, 2023, 02:02:50 pm
content: So I removed the cable from the power brick for about 1 hour, and flickering started when powering up again. The power LED did not flicker at all, so there's that.I'm assuming it's not the PSU. Can I troubleshoot further to narrow it down somehow? Someone mentioned inverter/cap temps.

author: Traceless
author_rank: Frequent Contributor
timestamp: May 19, 2023, 03:19:49 pm
content: Quote from: fiskmaas on May 19, 2023, 02:02:50 pmUnfortunately you can't rule out the power supply yet. While the LED dimming is an indicator for a problem with the PSU, just because the symptom doesn't show on your unit doesn't mean the power supply is okay. Getting a spare DC-Adapter for the screen might be the easiest way to proceed. Sometimes replacements from the original manufacturer are pretty expensive. In this case you can look for aftermarket ones on amazon. If you have a multi-meter you could check the DC-adapter's output voltage and see if it matches the specified voltage. If it is too low this points towards a faulty supply. However even if you see the correct output voltage that does not necessarily mean the PSU is okay (because you are measuring without a load).

author: fiskmaas
author_rank: Contributor
timestamp: May 19, 2023, 04:38:49 pm
content: Quote from: Traceless on May 19, 2023, 03:19:49 pmAllright, I checked with multimeter. Output is 19.5V. Rated 19V, 7.1A. Not sure I have anything that high voltage/amperage that I can swap with to be sure, but output looks ok at least.

author: fiskmaas
author_rank: Contributor
timestamp: June 28, 2024, 12:50:13 pm
content: Hey guys. So I've opened the monitor up and I'm trying to swap the backlight leds, as many of them have gone bad. Monitor is basically unusable with dark bands all over.I'm wondering, where do I even find replacement parts like this? I've searched a bit but I can't really find much. Am I shit out of luck?Attached a picture with part(?) number (E88441 94V-0 CS-1)

author: wraper
author_rank: Unknown
timestamp: June 28, 2024, 01:44:30 pm
content: Quote from: fiskmaas on June 28, 2024, 12:50:13 pmNo part number here, look in different place. Also search on aliexpress by LCD panel model. Might be ithttps://aliexpress.com/item/1005006741054300.html

author: fiskmaas
author_rank: Contributor
timestamp: June 28, 2024, 02:17:58 pm
content: Quote from: wraper on June 28, 2024, 01:44:30 pmYeah that looks to be the same. I've ordered it, let's see if it works. These are the only other numbers on there...Anyways thanks, hopefully it arrives in one piece!

author: fiskmaas
author_rank: Contributor
timestamp: July 11, 2024, 01:31:42 pm
content: I got the backlight today, and I swapped it out. It worked like a charm! There are no more dark spots andso farno more blinking either.Now I have some minor dirt and a couple small hairs I can see, but I can't seem to remove it. Is this from the backside of the LCD? I was pretty thorough cleaning the front but I guess I neglected the backside, lol.

author: Cubby
author_rank: Newbie
timestamp: August 15, 2024, 06:52:28 am
content: Hi Fiskmass,I have the exact same problem as you with my XV273K. Nobody repairs monitors where I am at. Could you tell me how you fixed the problem?My XV273K blinks on and off like what you posted.Is this a capacitor or backlight problem? I know it is not a PSU problem like some other poster suggested.Hope to hear back Thanks!