Why These Three Capacitors Fail In Many LG FLATRON LED Monitor?
In this article, the newcomers can learn (1) One of the major causes of device going dead (2) How and why a total dry solder patch up is absolutely necessary, especially in Power Supply Board and (3) Reasons for failure. (4) I have also included an easy method to open this type of monitor!
This Monitor belongs to the hospital where I work. The complaint was ‘dead.’ I opened and cleaned the inside of the monitor with the help of my colleague there.
Then carried the display with boards to home for troubleshooting.
I observed that three electrolytic capacitors had bulged in the secondary. So, replaced these and also did dry solder patch up of the board.
Then, when I checked giving power only to the PS Board, the outputs were ok.
Cleaned and lubricated the connectors. Then connected the boards and applied power to see the display gladly. Also seen is the three bulged caps.
Now, the question is why do these caps fail in LG Flatron Monitors? My presumption is that over a period of time, the stability of the control circuit is affected by dry solders (main causes), variation in values of components used especially the ESR of the caps etc. I think then a sudden power surge causes such capacitors to burst. Experts are invited to comment further on this subject.
Easy method to open this type of Monitor:
Place your finger tips of both hands firmly on the top side of the monitor in face up position without downward pressure on the screen so as not to break it at the tips, and lift the frame up. It will pop out of its holding brackets. Gently do the same on the corner sides, if necessary aided by a flat screwdriver inserted into the gap from the side, taking care not to damage the screen panel.
Follow this on all sides until the frame lifts up. Please do not pull it out, without detaching the front control button panel. Otherwise you are likely to damage the connecting strip wire. (Following is a picture of another monitor which I opened)
Mission accomplished with satisfaction getting added to its collection bag!
This article was prepared for you by Parasuraman Subramanian from India. He is 72 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.
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Paulo Brites
February 23, 2022 at 5:20 pm
Trying to answer about capacitor trouble I'd like to bring some ideas.
First of all I supposed theses cap are 105 C. This might be very important.
May be te quality, even beeing originals ones arent so good.
Nowadays the projects of electonics equipmente doesnt take in care climate conditions of any country like in a very far past years.
Should be interesting to search if your problem was an particular case or if is common to occur.
These are my modest contribuition to start a discussion about.
Tom Schupbach
February 23, 2022 at 8:55 pm
I agree about the capacitors, most new components, especially LG, are being built with sup standard parts. They will just pass the warranty period and then fail soon after.
The dry solder joints are caused by the use of ROHS solder (no lead) as it doesn't have the "wetting" ability of leaded. Anything that comes into my shop gets a proper rosin and lead solder fix if it's got cracked joints. I don't have time to resolder everything, but do look for the cracked ones under a microscope.
Parasuraman S
February 23, 2022 at 9:03 pm
Good inputs and very valuable too. Many thanks!
Jose virginio
February 25, 2022 at 7:33 am
Esses capacitores su scon 680uf trocaria por samyoung ou rubicon 105graus 680/50v ou 63v tamanho não altera tanto
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These capacitors su scon 680uf would exchange for samyoung or rubicon 105degrees 680/50v or 63v size does not change so much
Waleed Rishmawi
February 23, 2022 at 5:51 pm
thanks for sharing your repair thoughts and experience. have a blessed day
Parasuraman S
February 23, 2022 at 9:03 pm
Many thanks!
Mark
February 23, 2022 at 6:04 pm
Well done Parasuraman,
Those caps will get you every time!
Parasuraman S
February 23, 2022 at 9:04 pm
Ha! Ha! Yes, you are correct! Many thanks!
Anwar Y Shiekh
February 23, 2022 at 7:15 pm
Su'scon are tier 4 capacitors
https://www.tomshardware.com/reviews/power-supplies-101,4193-5.html
Parasuraman S
February 23, 2022 at 9:06 pm
Many thanks for the comments and link. As a thumb-rule, the electrolytic caps have a shelf life of only around six months. So, that's what causes trouble, when an equipment is idle for a longer time.
Anwar Y Shiekh
February 23, 2022 at 9:57 pm
I beg to differ on this conclusion.
Jose virginio
February 25, 2022 at 6:56 am
Minha tv lg 4k 4anos 12mil horas uso manutenção preventiva troquei esses capacitores su'scon por samyoung usei solda cardas quad ganhei mas qualidade em tudo. Tb tv ligado filtro linha panamax. Tou pensado trocar breve capacitores japonês linha rubicon genuino
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My lg tv 4k 4years 12mil hours use preventive maintenance I changed these capacitors su'scon for samyoung I used solder quad cards I gained but quality in everything. Tb tv connected panamax line filter. I'm thinking of changing Japanese capacitors, genuine rubicon line, soon
Jose virginio
February 25, 2022 at 7:29 am
Eu sempre troco capacitor uso 15-/- há mas voltagem capacitores 2mese atrás troquei vários capacitores eletrolítico meu receiver sony str de545 por melhores capacitores nichicon FG ficou show som limpo puro placa digital troquei tds 2capacitores elna selmic nichicon fg. Ex capacitor 470uf/6.5v substitui 470/10v ai por diante
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I always change capacitor I use 15-/- there is but voltage capacitors 2months ago I changed several electrolytic capacitors my receiver sony str de545 for better capacitors nichicon FG it was clean sound pure digital board I changed tds 2capacitores elna selmic nichicon fg. Ex capacitor 470uf/6.5v replaces 470/10v there on
Albert van Bemmelen
February 23, 2022 at 7:18 pm
When it are not just the e-caps that cause any problem it often will make these monitor repairs a lot harder.
Parasuraman S
February 23, 2022 at 9:07 pm
Yes, very true! Many thanks for your comments!
William Shaw
February 23, 2022 at 11:13 pm
Parasuraman, I think maybe you meant 6 years which is my understanding of them. Also, they do better with applied voltage as that seems to help the electrolyte last longer, so non-use is a contributing factor to their failure.
Parasuraman S
February 24, 2022 at 7:26 pm
No, six months only! Manufacturers recommend to bulk buyers to use caps within six months. Many thanks for your comments!
Jose virginio
February 25, 2022 at 7:05 am
Trocar capacitor com 6meses troquei su escon minha tv lg 4k por samyoung long life 10mil horas acredito ser melhor su'scon ganhei mas qualidade em tudo minha tv
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Change capacitor with 6 months I changed su scon my lg 4k tv for samyoung long life 10 thousand hours I believe it's better su'scon I won but quality in everything my tv
Rodolfo Gómez G.
February 24, 2022 at 5:46 am
Se me ocurre pensar en la opción de emplear capacitores al doble del voltaje, el abombamiento es por daño en el dieléctrico.
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It occurs to me to think of the option of using capacitors at twice the voltage, the bulge is due to damage to the dielectric.
Parasuraman S
February 24, 2022 at 7:27 pm
But size is a factor. We need to accommodate the cap in the space provided. Larger the voltage, larger the size! Many thanks for your comments!
Jose virginio
February 25, 2022 at 7:21 am
Na minha placa fonte minha tv lg 4k consegui alterar valor moderado su escon por samyoung ex.470uf/25v subs. 470uf/35v linha long life circuito led cap 27uf/160v subs 27uf/200v
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On my source card my lg 4k tv I managed to change moderate value su escon by samyoung ex.470uf/25v subs. 470uf/35v long life line circuit led cap 27uf/160v subs 27uf/200v
Jose virginio
February 25, 2022 at 7:13 am
Eu sempre troco capacitor uso 15-/- há mas voltagem capacitores 2mese atrás troquei vários capacitores eletrolítico meu receiver sony str de545 por melhores capacitores nichicon FG ficou show som limpo puro placa digital troquei tds 2capacitores elna selmic nichicon fg. Ex capacitor 470uf/6.5v substitui 470/10v ai por diante
=========================
I always change capacitor I use 15-/- there is but voltage capacitors 2months ago I changed several electrolytic capacitors my receiver sony str de545 for better capacitors nichicon FG it was clean sound pure digital board I changed tds 2capacitores elna selmic nichicon fg. Ex capacitor 470uf/6.5v replaces 470/10v there on
Anil Kumar V K
February 24, 2022 at 12:37 pm
Well done sir
Parasuraman S
February 24, 2022 at 11:15 pm
Many thanks!
Yogesh Panchal
February 24, 2022 at 3:52 pm
I think electrolytic capacitors do degrade if not used for a along time, Reason is chemical used in it. It would have dried up if temperature of storage/Use is not as per manufacturers specified range whether High or Low or due to material used substandard.
Parasuraman S
February 24, 2022 at 11:16 pm
Yes, good observation! Many thanks, Yogesh!
Felix Miata
May 22, 2022 at 1:41 pm
Are those three blue/white Su'scon 680uF 25V caps SL series? SL is 85° and used in Funai-manufactured home electronics power supplies and elsewhere where 105° are preferable. I've replaced many because of swelling.