LG Flatron CRT Monitor complaint: Hissing sounds

di1in · 19th July 2009, 14:00

I have a LG Flatron e700sh CRT monitor that has worked flawlessly for the last 4 years. But recently, especially in the last couple of months, it has started acting up. When i switch on the monitor it starts to emit a high-freq hissing noise. It sometimes also gets a little bit of whistle in it as well, similar to the sound which comes up when the AC gas in my car is low.
The monitor noise is unbearable at first(u can hear it in the nxt room) but gradually dies down and in about half an hour it's completely silent and back to normal. The screen and it's output is in no way visually affected by this, it still does it's job pretty well.

Does anyone have an idea as to what is going on with my monitor? Thanks in advance!

greenhorn · 19th July 2009, 14:24

Might be from either the LOPT or the coils/related circuitry.
Even if its neither of these, most TV service centers should be able to fix them.

SirAlec · 19th July 2009, 15:35

If you are a DIY o tell somebody to open it up and clean it up with a blower. the blower in vaccum cleaner wont do, you need a proper blower.

if still the problem persists, some caps might have leaked.

Abes · 19th July 2009, 17:32

May be it is telling you that its time to change over to a LCD Monitor.

Apart from whats mentioned in the above posts, i found this

Quote:

Usually if the monitor makes hissing and popping noises at the back it means that the connection from the LOPT (transformer) to the anode on the screen is loose, there is a way of fixing this but it wont always work. BEWARE THAT THIS IS VERY DANGEROUS. THERE ARE VOLTAGES IN EXCESS OF 30000 VOLTS AND THE TUBE CAN IMPLODE CAUSING A GREAT DEAL OF INJURY. THIS IS NOT FOR IDIOTS - YOU PERFORM THIS CHECK AT YOUR OWN RISK - I WILL NOT BE HELD RESPONSIBLE FOR ANY DEATH OR INJURY AS A RESULT OF THIS. THIS CAN KILL YOU. YOU HAVE BEEN WARNED!
Anyway, unplug your monitor and take the back off. The first thing you should see is a red cable going from the circuit board to the tube (the screen). You need 2 LONG metal screwdrivers WITH PLASTIC HANDLES. Slide 1 screwdriver underneath the plastic cup touching the metal prongs inside the plastic cup and hold the other screwdriver on the grey painted surface of the screen. Touch the metal parts of the screwdriver together and hold them there for at least 30 seconds. Slide your fingers underneath the plastic cup and pull it away from the tube. Check the 2 metal prongs for any sign of damage and if they are both OK then place them back in the hole making sure that the 2 prongs do not touch when they are in. Press the plastic cup gently, put the cover back on the monitor and then turn it on. If it continues to hiss and pop then it might be a problem with the LOPT its self which will need to be sent in for servicing to change it. Hopefully this advice will help and you wont kill yourself.

greenhorn · 19th July 2009, 18:03

Quote:

BEWARE THAT THIS IS VERY DANGEROUS. THERE ARE VOLTAGES IN EXCESS OF 30000 VOLTS AND THE TUBE CAN IMPLODE CAUSING A GREAT DEAL OF INJURY. THIS IS NOT FOR IDIOTS - YOU PERFORM THIS CHECK AT YOUR OWN RISK - I WILL NOT BE HELD RESPONSIBLE FOR ANY DEATH OR INJURY AS A RESULT OF THIS. THIS CAN KILL YOU. YOU HAVE BEEN WARNED!

Thats why I asked him to use a professional's services. even a turned off CRT can have significant amount of residual energy that can really harm you - this is a lot worse than getting a shock from mains. Even though i know my way around electronics ( can diagnose and repair ICE

) I stay the F away from CRT's and power eqpmt. And would suggest the OP to do the same

motionfreak · 19th July 2009, 18:16

Call LG service. They'll charge a minimum of 450/-, since ur monitor is out of warranty. Spares cost extra.
Same thing happened with my Samsung 17" CRT. Samsung guys repaired it with only minimum charge.

ashthedivx · 19th July 2009, 18:27

Nothing to worry more, Looks like transformer is gone kaput !! Most likely spares might be an issue for such an old model.

Still emphasis on getting it repaired !! Customer rulez

janitha · 19th July 2009, 19:05

I had a similar CRT (LG Flatron 700FT I think) with such problems along with display problems. LG technician first suspected LOPT and said if so original part is not available. Fortunately it was only some dry soldering. He told me if I wanted an LG bill, I will have to shell out > Rs.500/- but went satisfied with Rs.250/-. It is still with me in working condition and I would long have donated it but for the fear when again I have to send my Viewsonic for RMA. Incidentally, the problem with CRT almost always came with the rains.

aaggoswami · 19th July 2009, 20:20

Quote:

Originally Posted by greenhorn

. even a turned off CRT can have significant amount of residual energy that can really harm you - this is a lot worse than getting a shock from mains. Even though i know my way around electronics ( can diagnose and repair ICE

) I stay the F away from CRT's and power eqpmt. And would suggest the OP to do the same

Some people learn the hard way round. They realize only after getting a shock and feeling that they missed a disaster by an inch. They feel they are good DIY and they think if they can open a cylinder and fix things up, why not this smaller equipment.

Avoid opening and working on any power device. Working on CRT is not the best thing to do neither does it give pleasure if you are hard learner. Also the tools you use must be good quality.

di1in · 20th July 2009, 17:51

Thanks everybody ! Guess I'll have to stay away from that monitor until someone cures it or it zaps someone.

19th July 2009, 14:00	#1
di1in BHPian Join Date: Jan 2009 Location: Thrissur Posts: 511 Thanked: 293 Times View My Garage	LG Flatron CRT Monitor complaint: Hissing sounds I have a LG Flatron e700sh CRT monitor that has worked flawlessly for the last 4 years. But recently, especially in the last couple of months, it has started acting up. When i switch on the monitor it starts to emit a high-freq hissing noise. It sometimes also gets a little bit of whistle in it as well, similar to the sound which comes up when the AC gas in my car is low. The monitor noise is unbearable at first(u can hear it in the nxt room) but gradually dies down and in about half an hour it's completely silent and back to normal. The screen and it's output is in no way visually affected by this, it still does it's job pretty well. Does anyone have an idea as to what is going on with my monitor? Thanks in advance!
	() Thanks

19th July 2009, 14:24	#2
greenhorn BANNED Join Date: Apr 2007 Location: KL-01 Posts: 7,878 Thanked: 4,910 Times View My Garage	Might be from either the LOPT or the coils/related circuitry. Even if its neither of these, most TV service centers should be able to fix them.
	() Thanks

19th July 2009, 15:35	#3
SirAlec Senior - BHPian Join Date: Sep 2006 Location: zxc Posts: 3,393 Thanked: 727 Times	If you are a DIY o tell somebody to open it up and clean it up with a blower. the blower in vaccum cleaner wont do, you need a proper blower. if still the problem persists, some caps might have leaked.
	() Thanks

19th July 2009, 18:16	#6
motionfreak BHPian Join Date: Jun 2006 Location: Thane Posts: 195 Thanked: 68 Times	Call LG service. They'll charge a minimum of 450/-, since ur monitor is out of warranty. Spares cost extra. Same thing happened with my Samsung 17" CRT. Samsung guys repaired it with only minimum charge.
	() Thanks

19th July 2009, 18:27	#7
ashthedivx Senior - BHPian Join Date: Feb 2007 Location: Delhi Posts: 1,359 Thanked: 24 Times	Nothing to worry more, Looks like transformer is gone kaput !! Most likely spares might be an issue for such an old model. Still emphasis on getting it repaired !! Customer rulez
	() Thanks

19th July 2009, 19:05	#8
janitha BHPian Join Date: Feb 2009 Location: Kollam, Kerala Posts: 368 Thanked: 3 Times	I had a similar CRT (LG Flatron 700FT I think) with such problems along with display problems. LG technician first suspected LOPT and said if so original part is not available. Fortunately it was only some dry soldering. He told me if I wanted an LG bill, I will have to shell out > Rs.500/- but went satisfied with Rs.250/-. It is still with me in working condition and I would long have donated it but for the fear when again I have to send my Viewsonic for RMA. Incidentally, the problem with CRT almost always came with the rains.
	() Thanks

20th July 2009, 17:51	#10
di1in BHPian Join Date: Jan 2009 Location: Thrissur Posts: 511 Thanked: 293 Times View My Garage	Thanks! Thanks everybody ! Guess I'll have to stay away from that monitor until someone cures it or it zaps someone.
	() Thanks