LG L1960TR LCD - buzz / hum sound problem.


R

rpgs rock dvds

If I adjust the brightness on my new L1960TR LCD 19" monitor to any
value other than 100% (which is *way* too bright), the front panel
electronics make a constant humming / buzzing sound. It's not too
loud, but still annoying.

I wonder if it's a fault, or whether it's just bad design or
something.

I notice someone else made a user comment on ebuyer.com and mentioned
the same thing. I'm in two minds as to whether to contact customer
services and have it looked at - the problem being they might say
"it's normal" or something like that and then charge me for kind of
wasting their time or something!

Best regards, Robert.
 
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R

rpgs rock dvds

I'd just send it back and geta different brand.





- Show quoted text -
Unfortunately I've dragged my heels over this, and gone past the 28
days return to retailer time limit. It's still well under warranty,
but I'd now have to go through LG's servicing dept, and I'm nervous
about them telling me that they can't really find a "proper" fault
because you can hear the buzzing sound, but it's not like really loud
or anything, but it irritates me!
 
D

Dave Seven

rpgs said:
Unfortunately I've dragged my heels over this, and gone past the 28
days return to retailer time limit. It's still well under warranty,
but I'd now have to go through LG's servicing dept, and I'm nervous
about them telling me that they can't really find a "proper" fault
because you can hear the buzzing sound, but it's not like really loud
or anything, but it irritates me!
If it buzzes than it is faulty. RMA time.
 
J

Jordan Hazen

If I adjust the brightness on my new L1960TR LCD 19" monitor to any
value other than 100% (which is *way* too bright), the front panel
electronics make a constant humming / buzzing sound. It's not too
loud, but still annoying.
My 216BW does the same thing. Like you said, not very loud, but
enough to be a nuisance. It probably wouldn't bother me if I hadn't
worked to bring the rest of he system to near-silence (this hum
becomes unnoticeable when a fan, or seldom-used "loud" PC is running
nearby).

It appears that this sound is caused by vibrating coils and/or
capacitors in the display's backlight inverter circuit. Brightness
settings other than 100% are achived thorugh a PWM technique, cycling
the backlight on/off many times per second (sort of like a lamp dimmer
does), which causes the vibration and hum.

Sometimes I can make this noise disappear, or nearly so by thumping
the top of the display bezel a few times. It seems that the vibration
of components on its backlight circuit board get conducted to the
plastic case frame, causing that to resonate and amplify the sound.

Removing the back cover, and stuffing some small pieces of closed-cell
foam in between the metal PCB shielding and the case back helped a
little, but there unfortunately isn't enough room inside to fully
"suspend" or isolate the PCB.

Perhaps a coating of epoxy, or the hot-glue stuff often found on power
supply coils would make a difference? I haven't been brave enough to
try that just yet, as there's some risk it might contribute to
overheating.

I wonder if it's a fault, or whether it's just bad design or
something.
Mostly bad design, but many LCD panels seem to share the same flaw.
Manufacturers probably assume these will be run in a setting with
moderate background noise, where the hum won't be noticed.

Certain samples may be worse than others, though.

I notice someone else made a user comment on ebuyer.com and mentioned
the same thing. I'm in two minds as to whether to contact customer
services and have it looked at - the problem being they might say
"it's normal" or something like that and then charge me for kind of
wasting their time or something!
Even if you convince them to replace it, the new display's likely to
have the same flaw. So, I wouldn't bother trying that.
 
J

Jordan Hazen

My 216BW does the same thing. Like you said, not very loud, but
enough to be a nuisance. It probably wouldn't bother me if I hadn't
worked to bring the rest of he system to near-silence (this hum
becomes unnoticeable when a fan, or seldom-used "loud" PC is running
nearby).
Sorry for the double post, but I forgot to mention that this is a
Samsung display. I also have a 226BW, nearly identical but
manufacturered two months earlier, which is afflicted by the same hum
issue.

They're both excellent LCDs, otherwise.

On both panels, turning brightness all the way down to 0% (still
bright enough for most textual work) reduces the hum compared to most
intermediate settings, but it never goes away completely.
 
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R

rpgs rock dvds

Sorry for the double post, but I forgot to mention that this is a
Samsung display.  I also have a 226BW, nearly identical but
manufacturered two months earlier, which is afflicted by the same hum
issue.

They're both excellent LCDs, otherwise.

On both panels, turning brightness all the way down to 0% (still
bright enough for most textual work) reduces the hum compared to most
intermediate settings, but it never goes away completely.
THanks very much for your interesting post. I may return the monitor
and just try and say it's not good enough, and who knows they might
kind of bodge it so it reduces the noise somehow. Also, I'm thinking
of getting another monitor anyway, regardless of the outcome with LG
customer services / bodge department. The one I was thinking was this
one -

NEC MultiSync LCD2070VX-BK 20" TFT Monitor 1600 x 1200 300 cd/m2 800:1
5 ms DVI-D/VGA Black

http://www.ebuyer.com/product/139054

I really haven't the faintest idea whether it will be good or not -
just too tired to look around for anything else ATM. I want one
that's good for both text and games. Don't care about dvds.

Thanks, Best regards, Robert.
 
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