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LG 38GL950G - 3840x1600/G-Sync/144Hz

Discussion in 'Monitors' started by Legend, Dec 19, 2018.

  1. Keelolo

    Associate

    Joined: Oct 24, 2012

    Posts: 15

    If you're worried it#s used - theres an option in the menu where you can see in the menu the total uptime of your monitor
     
  2. ozzaman

    Gangster

    Joined: Oct 23, 2006

    Posts: 358

    Ah thats helpful! thanks for the tip.

    So 'Information' tab under the 'General' settings states that the 'Total Power on Time: 119 Hours'. Seeing as I received the monitor yesterday and only managed to switch it on in the evening.. I am going to take a wild stab and say I haven't had the thing on for 119 hours.
     
  3. Keelolo

    Associate

    Joined: Oct 24, 2012

    Posts: 15

    I finally couldn’t take the hissing noise anymore decided the throw caution to the wind and crack open the monitor.

    getting the rear cover off is a real pain due to the number of clips, but once done the cover comes straight off

    I turned the monitor on whilst the back was off and the hissing noise is not coming from the side fan, in fact it was motionless during my testing.

    I then set about trying to access the main GSync fan, It’s definitely not for the feint hearted. You need to remove the led strips and the mount, unclip loads of cables, then unscrew the main PCB module from the panel

    after removing from the panel you need to extract the pcb from the shielding. Once done the fan is clearly visible. I removed the fan and manually spun it - there was clear bearing noise and this was very similar to the hiss that I was hearing. I’m pretty confident this is the source.

    tried to fix by dropping a bit of oil into the bearing and also copper grease on the spindle. It didn’t seem to make a difference as I could still hear the bearings when spinning it manually. I could see the thermal paste had been squeezed out from between the heat sink and the die and decided to replace this with some thermal grizzly. The old paste was quite thickly applied and this possibly explains my high die temperature reading in the service menu. The thermal grizzly brought this down to 57C with the back cover off so it seems to have improved temps. Unfortunately, the GSync fan seems to kick in about 50C (monitored via the service menu) so it didn’t bring this down enough to prevent the hissing sound from coming back

    I think for me the only solution is to see if I can source a replacement fan and hope that is better.

    If anyone else has this hissing sound and is in their return window I suggest you return it - you have take the whole thing apart to get to that GSync fan
     
  4. Vega

    Wise Guy

    Joined: Dec 12, 2010

    Posts: 1,567

    Location: Washington D.C.

    Ya that is a shame someone sold you a used monitor for new? Should be a crime. When I powered on my 38LG, it said something like 1 hour (factory test I'm sure) and of course colors were 50/50/50.
     
  5. Sibbers

    Associate

    Joined: Jun 15, 2017

    Posts: 53

    Cheers for taking the plunge and clearing that up. Don’t suppose you got any pics and/or know what fan specs are for the gsync fan?
     
  6. Azrael1

    Wise Guy

    Joined: Aug 11, 2004

    Posts: 1,487

    Location: Kettering

    Thank you ever so much for doing all of that work and getting the info. I think this has definitely put me off buying one. Especially at that price point.
     
  7. Keelolo

    Associate

    Joined: Oct 24, 2012

    Posts: 15

    Some teardown photos for those that like a bit of electronic p*rn

    Rear panel off, led gubbins removed
    [​IMG]

    Main PCB module removed from panel and flipped over
    [​IMG]

    PCB removed from housing showing fan assembly over GSync module
    [​IMG]

    Heatsink removed - note thick layer of paste
    [​IMG]

    GSync fan
    [​IMG]
     
  8. Sibbers

    Associate

    Joined: Jun 15, 2017

    Posts: 53

    Cheers for the pics and info!

    Looks like a 60mm 5v pwm fan that runs up to 3k rpm, but height wise it’s ~13mm and it needs to be without a housing so that’ll reduce the chances of finding a directly replaceable alternative.

    Specs here: https://www.delta-fan.com/Download/Spec/AFB0705MC-00F0R.pdf

    I take it there’s not more room for a taller fan as it’s sandwiched into place, right?

    I think better paste and heat pads is probably a good idea - thermal grizzly pads did wonders for my motherboard VRMs but I suppose it’s the processor that is all important for temp sensing.

    I only ever really think of noctua when I want quiet fans with good bearings, but they don’t do fans that are this low profile.

    Has your work paid off or do you think you’ll be back in again soon if you can find an alternative?
     
  9. ozzaman

    Gangster

    Joined: Oct 23, 2006

    Posts: 358

    Great work Keelolo!

    Getting quieter fans would obviously solve any fan noise issues however for me personally, the most annoying noise is the coil whine. As far as I am aware there is no cure for coil whine.

    Do you think its the G Sync module with the coil/transistor whine? I suppose its worth considering the other 38inch models without the module..
     
  10. Keelolo

    Associate

    Joined: Oct 24, 2012

    Posts: 15

    I ordered a replacement GSync fan (same model) from Mouser in the US - the fan is pretty cheap but once you add in the VAT and Shipping it cost £25.

    I'm happy to report that the hissing sound has gone away - there is still a slight warble from the the new fan (if you put your head right next to the monitor) but it is most definitely 'quiet' compared to the old fan.

    So, if you have a hissing sound from the monitor it is most likely a bad fan - see https://forums.overclockers.co.uk/posts/33438986 for a previous post in this thread for a clearer recording of the noise from another user. Mine was exactly the same.

    So, thanks for nothing LG - there was clearly a problem but you refused to stand by your warranty and recognise the issue.
     
  11. niko

    Hitman

    Joined: May 29, 2005

    Posts: 859

    Location: oswestry shropshire

    it is a crime, selling used as new.
     
  12. Sibbers

    Associate

    Joined: Jun 15, 2017

    Posts: 53

    Yeah poor show by LG, but really glad it happened to you so we got to find out so much conclusive stuff and that you have sorted it out and improved heat transfer with better paste - I have to admit the temptation to use conductonaut would exist for me. Hopefully some known to be very quiet fans come along and once out of warranty maybe I'll dig in and have a go myself.
     
  13. Keelolo

    Associate

    Joined: Oct 24, 2012

    Posts: 15

    I don’t think the paste made much difference in the end - the low temp (57C) was running with the rear cover off. Once I replaced the fan and put the cover back on, the temp went back up to 74C-ish. Not surprisingly really, the mount for the monitor covers the ventilation holes directly above the GSync fan
     
  14. gorillahead

    Associate

    Joined: May 13, 2020

    Posts: 15

    Update! So i got my second monitor. I put them side by side. Compared image and fan sound and looked for dead pixels


    Here is what i discovered.

    No dead pixels.
    The screen was not as white on my new monitor, it was a slightly darker white. The setting where identical on both monitors. Every single setting. This bothered me at first. It was like when you switch from an iphone 8 to an iphone x and the X has a little bit of a yellow tint.


    But heres why i kept the new replacement. The black light bleed was way better. It was like reduced tremendously. The screen was way more uniform when it was black in a dark room.

    The new monitors fan was slightly quieter less of a hum

    lastly the new monitor was manufactured may 2020 the last one was march 2020 but what i found interesting is the power brick for the old one was version 1.2 and the new one was 1.4.
     
    Last edited: Jun 6, 2020
  15. drnutta123

    Associate

    Joined: May 3, 2007

    Posts: 3

    Bit annoyed from what you found... my monitor is a week old... but the manufacture date is DEC 2019. In normal mode 60hz seems ok... its when you jack up the refresh rate and wait lets say 30mins before you hear a high pitch sound.
    No dead pixel... but feel i need to return it one... due to date of manufacture and worried this sound will get worse. The power brick states version1.
     
  16. Sibbers

    Associate

    Joined: Jun 15, 2017

    Posts: 53

    My power brick is v1, pretty sure manufacture date is Nov 2019 based on the service menu - I have no funny noises. Honestly I wouldn't expect the more recent versions to be better because of improvements, I'd imagine it's more likely just plain old variation either in panel or assembly. My panel was slightly more red than the review model TFTCentral got, but I've calibrated now and it's all good. I think it can be easy to get bummed out because you have an older version, but I think its psychological and its easy for confirmation bias to creep in and colour your view about what you have - keep it simple and stay sane. If you're not satisfied, just return it. Imo anyway.
     
  17. gorillahead

    Associate

    Joined: May 13, 2020

    Posts: 15

    My thoery on why the power bricks differ was that they somehow alter the temperature of the backlight through the power source Depending on the panel used.
    I honestly wouldnt be upset. The fan thing though i do understand you. they all have fans and they will have a sound and of u dont hear its because you don't hear certain frequencies either due to age or aged hearing.
     
    Last edited: Jun 6, 2020
  18. drnutta123

    Associate

    Joined: May 3, 2007

    Posts: 3

    thanks for the input guys!
     
  19. ozzaman

    Gangster

    Joined: Oct 23, 2006

    Posts: 358

    I am in the middle of returning my 38GL950G but contemplating whether to get a replacement or refund. As the WN is being released shortly, I am tempted to go for that panel to avoid the fan issues (assuming it has no fans) and transistor noise.

    My question was around the the difference between the gsync module and gysnc compatible monitors. Has anybody had experience with using both? Did you notice a huge difference in quality between the two?
     
  20. skuko

    Gangster

    Joined: Oct 13, 2005

    Posts: 307

    could you muster the will to create a simple guide for the disassembly and replacement? i returned my first unit a couple of weeks ago, but i still want this screen, even if i have to replace the fan myself, but i really want to avoid damaging anything as much as possible. also, can you please link where you ordered the replacement fan exactly?

    thanks mate.