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Repaired my Samsung LCD monitor.

Started by Jan Panteltje November 3, 2011
Repaired my Samsung LCD monitor.
Started making a ticking noise yesterday, display flashing on / off one per second.
Switching it on and off and setting brightness lower made it work.
This morning same thing, but no way to get it working.
It was at Samsung for repair in the guarantee period, but now
long past guarantee, on 12 hours a day, now for lets see 6 or seven years?
So, as no guarantee, nothing to lose to break it open.
And that is what is required, just break it open, crack... crack,
pulling apart those plastic edges but it opens without damage.
Took out the power supply board (switcher) sure enough, electrolytics
all swollen, 2 small 1000uF/25V in parallel.
Replaced by one 2500uF/35V, and against all odds it is working again.
Measured the old caps, maybe 200uF left each, ESR seemed OK though, strange.

Maybe - for the paranoia conspiracy theorists - electrolytics
are an evil plot by manufacturers to create a defined short lifespan,
so people will buy new stuff.
That, and new standards :-)


On Thu, 03 Nov 2011 13:32:59 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

>Maybe - for the paranoia conspiracy theorists - electrolytics >are an evil plot by manufacturers to create a defined short lifespan, >so people will buy new stuff. >That, and new standards :-)
Some Chinese company used a bad chemical formula obtained through industrial espionage and managed to get a whole slew of their caps into a wide variety of products (including my Gateway monitor) which have an incredible failure rate as the caps crap out. http://en.wikipedia.org/wiki/Capacitor_plague Did your bad caps have a green plastic wrapper on them by any chance? The bad one on my GW monitor power supply board did. Dave
On 11/3/2011 3:08 PM, dav1936531@is.invalid wrote:
> On Thu, 03 Nov 2011 13:32:59 GMT, Jan Panteltje > <pNaonStpealmtje@yahoo.com> wrote: > >> Maybe - for the paranoia conspiracy theorists - electrolytics >> are an evil plot by manufacturers to create a defined short lifespan, >> so people will buy new stuff. >> That, and new standards :-) > > Some Chinese company used a bad chemical formula obtained through > industrial espionage and managed to get a whole slew of their caps > into a wide variety of products (including my Gateway monitor) which > have an incredible failure rate as the caps crap out. > > http://en.wikipedia.org/wiki/Capacitor_plague > > Did your bad caps have a green plastic wrapper on them by any chance? > The bad one on my GW monitor power supply board did. > Dave
There were the crappy caps (I have two dead mobos as a testament to Chinese engineering AKA espionage), but in the last twenty years, we have been abusing caps with SMPS. Everything used to be linear, and the electrolytics lasted much longer.
Jan Panteltje wrote:
> Repaired my Samsung LCD monitor. > Started making a ticking noise yesterday, display flashing on / off one per second. > Switching it on and off and setting brightness lower made it work. > This morning same thing, but no way to get it working. > It was at Samsung for repair in the guarantee period, but now > long past guarantee, on 12 hours a day, now for lets see 6 or seven years? > So, as no guarantee, nothing to lose to break it open. > And that is what is required, just break it open, crack... crack, > pulling apart those plastic edges but it opens without damage. > Took out the power supply board (switcher) sure enough, electrolytics > all swollen, 2 small 1000uF/25V in parallel. > Replaced by one 2500uF/35V, and against all odds it is working again. > Measured the old caps, maybe 200uF left each, ESR seemed OK though, strange. >
Samwha XC? Three days ago Olaf Kaluza from the German NG found exactly the same problem in his sister's Samsung monitor, bulging electrolytics.
> Maybe - for the paranoia conspiracy theorists - electrolytics > are an evil plot by manufacturers to create a defined short lifespan, > so people will buy new stuff. > That, and new standards :-) >
We have a Hammond organ from 1961 where the designer did a major screw-up by placing the electrolytic right next to the toasty rectifier tube. Just to make sure it can't freeze over, I guess. Surprisingly it is still good 50 years later. -- Regards, Joerg http://www.analogconsultants.com/
On a sunny day (Thu, 03 Nov 2011 18:08:57 -0400) it happened
dav1936531@is.invalid wrote in <mq36b7hnnfnjlgov0tuksrae9mban0mitv@4ax.com>:

>On Thu, 03 Nov 2011 13:32:59 GMT, Jan Panteltje ><pNaonStpealmtje@yahoo.com> wrote: > >>Maybe - for the paranoia conspiracy theorists - electrolytics >>are an evil plot by manufacturers to create a defined short lifespan, >>so people will buy new stuff. >>That, and new standards :-) > >Some Chinese company used a bad chemical formula obtained through >industrial espionage and managed to get a whole slew of their caps >into a wide variety of products (including my Gateway monitor) which >have an incredible failure rate as the caps crap out. > >http://en.wikipedia.org/wiki/Capacitor_plague > >Did your bad caps have a green plastic wrapper on them by any chance? >The bad one on my GW monitor power supply board did. >Dave
No they were black.. Yes I have read about those defective caps, I think Dell had them in their PCs too. I seem to have lots of bad electrolytics, replaced on my PC motherboard, one power supply, I bought a new power supply for the PC on ebay, this time a 600W with 45 Amps at 5 V, and it still is hardly able to run things, I opened it up, and the filter caps are very very small on the +5, I mean small mechanically, I scoped the 5 V under load, lots of RF.. Seems the Chinese saved on caps... Anyways, it seems current designs go for a lifetime of just past guarantee, and the best way to do that is fit a specific quality electrolytics. Maybe there still is money in LCD monitor repair....
On a sunny day (Thu, 03 Nov 2011 15:43:00 -0700) it happened Joerg
<invalid@invalid.invalid> wrote in <9hgjnsFtqaU1@mid.individual.net>:

>Jan Panteltje wrote: >> Repaired my Samsung LCD monitor. >> Started making a ticking noise yesterday, display flashing on / off one per second. >> Switching it on and off and setting brightness lower made it work. >> This morning same thing, but no way to get it working. >> It was at Samsung for repair in the guarantee period, but now >> long past guarantee, on 12 hours a day, now for lets see 6 or seven years? >> So, as no guarantee, nothing to lose to break it open. >> And that is what is required, just break it open, crack... crack, >> pulling apart those plastic edges but it opens without damage. >> Took out the power supply board (switcher) sure enough, electrolytics >> all swollen, 2 small 1000uF/25V in parallel. >> Replaced by one 2500uF/35V, and against all odds it is working again. >> Measured the old caps, maybe 200uF left each, ESR seemed OK though, strange. >> > >Samwha XC? Three days ago Olaf Kaluza from the German NG found exactly >the same problem in his sister's Samsung monitor, bulging electrolytics. >
Dunno, sure looked at it, but alread threw them away, It think it is a hint, I have seen people post here who then tried to replace the backlight inverter etc... Better to check for swollen caps, the backlight inverter runs on the same switcher output. With swollen caps I mean the little cross at the top of the electrolytic bulging, or worse the rubber at the bottom coming out and the cap ending up away from the board.
>> Maybe - for the paranoia conspiracy theorists - electrolytics >> are an evil plot by manufacturers to create a defined short lifespan, >> so people will buy new stuff. >> That, and new standards :-) >> > >We have a Hammond organ from 1961 where the designer did a major >screw-up by placing the electrolytic right next to the toasty rectifier >tube. Just to make sure it can't freeze over, I guess. Surprisingly it >is still good 50 years later.
There are likely no high peak currents with a tube rectifier.
>-- >Regards, Joerg > >http://www.analogconsultants.com/ >
Jan Panteltje wrote:
> On a sunny day (Thu, 03 Nov 2011 15:43:00 -0700) it happened Joerg > <invalid@invalid.invalid> wrote in <9hgjnsFtqaU1@mid.individual.net>: > >> Jan Panteltje wrote:
[...]
>>> Maybe - for the paranoia conspiracy theorists - electrolytics >>> are an evil plot by manufacturers to create a defined short lifespan, >>> so people will buy new stuff. >>> That, and new standards :-) >>> >> We have a Hammond organ from 1961 where the designer did a major >> screw-up by placing the electrolytic right next to the toasty rectifier >> tube. Just to make sure it can't freeze over, I guess. Surprisingly it >> is still good 50 years later. > > There are likely no high peak currents with a tube rectifier. >
No, but what really kills electrolytics is heat. After an hour you can't touch that cap anymore ... phssss ... ouch. -- Regards, Joerg http://www.analogconsultants.com/
On a sunny day (Fri, 04 Nov 2011 07:58:59 -0700) it happened Joerg
<invalid@invalid.invalid> wrote in <9hictoFdj4U2@mid.individual.net>:

>Jan Panteltje wrote: >> On a sunny day (Thu, 03 Nov 2011 15:43:00 -0700) it happened Joerg >> <invalid@invalid.invalid> wrote in <9hgjnsFtqaU1@mid.individual.net>: >> >>> Jan Panteltje wrote: > >[...] > >>>> Maybe - for the paranoia conspiracy theorists - electrolytics >>>> are an evil plot by manufacturers to create a defined short lifespan, >>>> so people will buy new stuff. >>>> That, and new standards :-) >>>> >>> We have a Hammond organ from 1961 where the designer did a major >>> screw-up by placing the electrolytic right next to the toasty rectifier >>> tube. Just to make sure it can't freeze over, I guess. Surprisingly it >>> is still good 50 years later. >> >> There are likely no high peak currents with a tube rectifier. >> > >No, but what really kills electrolytics is heat. After an hour you can't >touch that cap anymore ... phssss ... ouch.
It is true that these electrolytics have lifetimes related at some temperature, but looking a the the mechanism that actually destroys them, such as losing the electrolyte, and that indeed could happen faster at elevated temperatures, it seems some do, and then some do not. I have opened elcos for inspection, exploded ones opened themselves :-) Anyways maybe they can be manufactured in a way that they stay intact. It is that old cost versus profit thing I suppose. In the sixties I had a request for a design for a railroad crossing system, and they required something like 40 years of guaranteed working, No manufacturer I could find wanted to guarantee electrolytics for even 10 years.
On Nov 4, 9:58=A0am, Joerg <inva...@invalid.invalid> wrote:
> Jan Panteltje wrote: > > On a sunny day (Thu, 03 Nov 2011 15:43:00 -0700) it happened Joerg > > <inva...@invalid.invalid> wrote in <9hgjnsFtq...@mid.individual.net>: > > >> Jan Panteltje wrote: > > [...] > > >>> Maybe - for the paranoia conspiracy theorists - electrolytics > >>> are an evil plot by manufacturers to create a defined short lifespan, > >>> so people will buy new stuff. > >>> That, and new standards :-) > > >> We have a Hammond organ from 1961 where the designer did a major > >> screw-up by placing the electrolytic right next to the toasty rectifie=
r
> >> tube. Just to make sure it can't freeze over, I guess. Surprisingly it > >> is still good 50 years later. > > > There are likely no high peak currents with a tube rectifier. > > No, but what really kills electrolytics is heat. After an hour you can't > touch that cap anymore ... phssss ... ouch. > > -- > Regards, Joerg > > http://www.analogconsultants.com/
OK, we will watch out for Chinese electrolytic caps thanks for tips