CHG90 - Power-On Display Issue (Glitch on cold-boot from sleep/low-power mode)

[rlaphoenix]

The problem
 

 

If I leave this monitor off for at least 8 minutes~, then try to power it on, it will glitch for usually 17+ minutes before fixing itself. The weird colorful lines will slowly change how they look, slowly going away. Most people have this happen for 10-15 seconds, but not me, I can cook a frozen pizza while waiting to jump on my PC. I don't remember exactly when I noticed it for the first time but it wouldn't have been more than 1 year of use.

 

I've now had this monitor for just over 6 years and attempted RMA or exercise my warranty after around 1-2 years of use. Why not sooner? Since it's an issue that (eventually) fixes itself I initially just carried on my day as I have stuff to get done and returning the monitor for more support woes and delays and no monitor for months wasn't an option. Nowadays I have options if my monitor has to be sent off for a bit or whatever, but at the time it was not an option. Clearly this was a mistake. I should have went to Samsung much sooner.

 

Glossary:

• Exact Model: LC49HG90DMUXEN
• Current Firmware: m-HG949CCAA-1025.0 (Released sometime in 2021 exclusively on Samsung Korea's support page)
• Connected via: DisplayPort
• Resolution: 3840x1080
• Refresh Rate: 144 Hz
• Something(?): 166.7 kHz (listed next to the refresh rate in Monitor Settings -> Information)

 

Related threads:

 

Support woes

 

Around 2019 or 2020 I contacted Scan.co.uk about it as it got annoying (yet still not as bad as it is today) so I contacted and tried to get it RMA'd or repaired or something under warranty. I was told by Scan.co.uk that it had no warranty as I needed to contact them within 14 days of purchase. Yet they tried to get me to cancel my order, canceled it a day after I told them not to, and then delayed shipment for ages. There was no way for me to have seen the issue and contact them within 14 days of purchase. Even if the 14 days was from the delivery date, they never added the tracking on this order and left it as "despatched" status,

so they couldn't prove when it was delivered and they told me to ask Samsung instead.

 

Samsung rejected my warranty and told me to contact very dodgy "repair partners" and their Irish list had only links to businesses that either changed their name or just shut down or something. I contacted them again to ask for one that is still in business and they gave me a really dodgy email to somewhere with no business information online. They (the repair partner) responded to me by email saying it would cost something around €100 euro or more just to come out and take a look at it, of which they will then go off buy the parts, send me an invoice for the parts and then invoice me again to come back down and install the parts if that was even the issue in the first place. I.e., apple-level repairs by an extremely dodgy business.

 

Fine... What can I do myself?...

 

Discussions surrounding the repair of this solution are extremely fragmented. Everyone seems to have a different fix with most coming back saying it didn't actually work with the issue coming back down the line. Most people who said they fixed it probably had the issue come back (or rather it didn't actually fix but they didn't see it until a later time) and just didn't bother coming back and updating their post. There's also an issue where this problem only occurs on one half of the monitor, or for most both parts of the monitor. For context, this monitor is 2x panels powered and is sort of pooled as one monitor internally.

 

"Solutions" I've seen include:

• Updating the monitor firmware to either the latest version, a specific version, or the version on the Samsung Korean support page as it has the highest firmware version number and is likely the "final" firmware version to come out just not internationally.
• Trying a new HDMI or DisplayPort Cable.
• Using HDMI port instead of the DisplayPort Cable, or the other way around. As in if you use DisplayPort, try using HDMI instead, or the other way around. Assuming that one of the ports on the monitor is faulty. However, I believe if this is a fix for some people it's actually because of the next "solution" because of the HDMI port's limitations compared to DisplayPort.
• Reducing the maximum Refresh Rate in the monitor settings from 144 Hz to 120 Hz or 100 Hz. For some, the lower power requirements for these lower refresh rates solved the issue. However, even if this worked, I'm paying for 144 Hz, not 120/100 Hz. Also, most people only say this as a solution because when it has nearly fixed itself changing the refresh rate from 144 Hz to 120/100 Hz usually instantly fixes it. As in, speeds up the last tail end of it fixing itself. I don't think this is actually a fix to prevent it from happening in the first place.
• There's a rare amount of discussion (therefore little info) saying that if you take "the board" (not sure which) and push it "away" from the "metal" it fixes itself (possibly meaning the power board or main board is shorting against it's shield or the monitor frame). This is genuinely likely as well. One of those discussions say they fixed it by putting a Q-Tip between "the board" and (something) to fix it. I can't remember where I heard this either, so I cant reference it.
• And of course, replacing components is brought up. I have not found any online discussion saying they could fix it themselves by replacing one or more components. The only posts I can find where they got it fixed by replacing components is those who had Samsung Technicians come round to repair it themselves, with one post saying they basically replaced everything, specifically the 2x panels and mainboard and powerboard. I doubt replacing all of them is necessary though. I also saw discussions about replacing the cables that connect the power and main boards with the panels but have never seen anyone do it and come back to tell their story.

What I have done so far is:

• Updating the monitor firmware to my local Samsung website's support page's latest firmware (ver 1021.0, 2020.09.15): https://www.samsung.com/ie/support/model/LC49HG90DMUXEN/#downloads
• Updating to various specific firmware versions suggested over the years, none that I can specifically remember, they never made a single difference from what I saw.
• Updating to the Korean version 1025.0 which seems to be the last firmware released in 2021 some time.
• Trying a new DisplayPort cable (I've switched cable many times over the years). I have not tried using the HDMI port at least from what I recall, but I doubt it will do a thing.
• Plugging into a different device (I've changed GPUs and reinstalled Windows a few times over the years).
• Reducing the maximum Refresh Rate in the monitor settings to 120 Hz for around a week. Made no difference.
• Today (May 8th, 2024) I replaced the Power Board from a Rev: 1.1 Date: 2017.5.15 to one from Aliexpress that is the same revision and date. All other identifiers on both boards from what I could tell matched exactly. The only difference I could notice was the color of some components like resistors being white with stripes vs. pink with stripes and so on. Therefore, I believe it's the exact same board. The Aliexpress seller expressly states that the issue I have is not the board but something else. However, what does he know, he could just be saying that to not get the order refunded. Note: I could be wrong but it seems to fix itself faster since I put in this new board though. It used to take 17+ minutes (I timed it) but now it takes considerably less (I have not timed it, and I could be wrong, but it does seem to be a lot faster).

What now?

I'm here to ask if anyone else has had this issue or perhaps any ideas on stuff I could try. I'm all ears for stuff to try. Does anyone know anyone who had successfully repaired this issue on any Samsung monitor? I was extremely adamant that the power board was the issue, but I guess not. Unless the power board I got also exhibited this issue (perhaps why it's being sold as a gutted part?).

 

By the way, I tried to buy the newer 1440p higher-curve non-OLED version from Amazon.co.uk and they also blue balled me for over a month with no shipping updates or communication. Just took my money and left me in the dark. So even if I wanted to just ditch this for a newer model, I can't. 32:9 master race is pretty difficult to have in Ireland, I suppose...