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  • EEVblog #347 – Bad Cap LCD Monitor Repair

    Posted on September 11th, 2012 EEVblog 23 comments


    Forum Topic HERE
    Repairing and replacing the bad caps in a Samsung SyncMaster 204e LCD Monitor found while Dumpster Diving.

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    • http://www.eevblog.com/ Jan

      Another good example of planned obsolescence. Many other SAMSUNGs had died the same way. When I am repairing that stuff, I try to replace the caps with next higher voltage value.

    • http://charlespax.com Charles Edward Pax

      I had the exact same problem with my 204B. After replacement it worked just fine.

    • Steve

      Had exactly the same problem with my ViewSonic about a year ago. Stopped working, changed a bulged no-name cap and it kinda worked. Got a display, but colours all wrong and calling up the settings menu just crashed the OSD. Found a e2 and shorted the SDA to VCC, and as expected, it went back to defaults and corrected everything.

      Actually, I think the short to VCC is still in there. Oops. Ah well.

    • SD

      Been there, done that. I also found bad soldering on a cheap no-name that I was going to throw out.

      Just a disassembly hint. According to the service manual for a similar model the proper way to open the case is to shove your fingers between the screen and bezel.

      THe no-name was easier to disassemble as they did use screws.

    • http://www.youtube.com/watch?v=XJTfdDTAQpo gest

      I had the exact same problem on my Samsung LCD TV. About 2 years after bought, just out of warranty, Samsung wouldn’t fix it. I found out it was rampant and Samsung eventually sued in USA with a class action lawsuit but many people never got any money.

      I made a video about it and kept noticing how many more people were being affected every day:

      http://www.youtube.com/watch?v=XJTfdDTAQpo&sns=em

      Watching Dave’s video I remembered the exact same thing with me. Not sure which caps brand, but on my LCD they were under-rated voltage… Somebody decided to use 10 V caps on a 12 V bus. Also next to heat sink on the power supply, 2 caps failed obviously but rest seemed ok. The replacements were also huge for the space, but I got them to fit (as you can see by the video).

      By the way my TV still working ok and it has been about 1.5 years since my solder job as you can see by the upload date on the Youtube video.

    • Jay Ts

      Dave !!

      I hope you saved those old caps!

      You can add me to the “me too” list; I’ve also been there and done that. In my case, it was an Acer monitor, and I needed to have it back in use ASAP. It had one bad cap, and I replaced it with a Nichicon found in my design kit. Sometimes I like to live dangerously: I will wait to see how long it takes for any of the others to fail, too.

      I wish I had written down the sizes and specs for all the other caps. I was in too much of a hurry, unfortunately. I should have done that so I could order high-quality replacements from Mouser and replace them all later. I would make sure to get 105° ratings, and higher voltage ratings, both of which help with reliability.

      Now about the failed caps: I did a “teardown” of the failed cap, alongside a Nichicon cap of similar specs I had on hand. The difference was just amazing! The failed cap reminded me of capacitors made in the 1950s! Really, really, unbelievably horrible, and I mean that. :) Nowadays, no one has any excuse to use something that bad in any kind of electronic equipment! They should not even be manufactured. To give you a hint, I could make capacitors out of aluminum foil, newspapers, and a soda can, and they would be no worse.

      If I had time and video equipment, I would love to show this to people. Can you do it? The world deserves to know, Dave! Let’s see if we can stop this horror! :-D

    • http://ebidk.blogspot.com ebidk

      The Samsung SyncMaster 226BW has a similar, if not the same power supply, and usually get a problem where the backlight flash. This can also be fixed by replacing a few capacitors: http://ebidk.blogspot.com/2010/02/repairing-flashing-backlight-problem-on.html

    • David

      I’ve done this several times. The manufactures HAVE to know about this problem with the crappy caps by now. Ergo – planned failure.

    • f4eru

      10°C higher temp => expected lifetime cut in half

      replace 85°C by 105 => 4x the lifetime at the same temp.

      does somebody know the influence of the voltage on lifetime ?

      • SD

        If you trust MIL-HDBK-217F Notice 2 for an aluminum electrolytic capacitor it is exponential pi_v=(S/0.6)^5+1 where S is the ratio of voltage to rated voltage.

        It also states temperature rating doesn’t matter, as long as it is not exceeded. It only uses actual temperature.

        Of course this is all based on data from 1995 or earlier.

    • http://www.siliconchip.com.au Nicholas

      Interesting that Jaycar sold you SI brand caps. Normally when I buy low-ESR caps from them they are “Suntan” or “Samxon” brand and seem quite OK.

      If you’re ordering replacements from element14, Digi-Key, Mouser, etc then it’s worth looking at the cap data sheets. While low-ESR caps are good, some are rated for 2000 hours operation at 105 degrees while others may be rated for 3000 or 5000 hours. The higher-hour ones will of course be more expensive and hopefully they are operating well below 105 degrees anyway but if you really want them to last, go for the long-life types.

      I tend to keep a selection of low-ESR caps on hand, ranging from 100uF 16V up to 2200uF 50V. Futurlec sell cheap enough low-ESR caps that you can afford to keep a selection and thar range should suit most power supplies. They aren’t top quality but nor are they rubbish (usually Samxon or Elna). That way I’ll generally have the caps I need for a similar repair to this.

      Rockby also sometimes have some decent brand caps very cheaply in their weekend sales – less so these days but still worth checking. I’ve gotten a lot of pretty nice Korean-made (eg, Samwha) and Japanese-made electrolyc caps from them over the last few years, for cents each.

      • http://www.eevblog.com EEVblog

        Yes, I think Jaycar show and image of the Samxon brand in their catalog.

    • Katrina

      Dave, you are the man. My Samsung died for about a year, and I have been saving money to get a new one. Replaced 2 bulged caps, and it is working now! That’s a lot of money saved.

      Bless you!

    • DarkSider

      Thanks for the very helpful video Dave! The “capacitor plague” problem is well discussed in an interesting Wiki article.

      High failure rates have been known in consumer electronics equipment since the early-mid 2000s.
      There are also some notes about industrial espionage being implicated in the low cost Taiwanese electrolytic capacitors. Worth reading.

      http://en.wikipedia.org/wiki/Capacitor_plague

    • http://www.dgkelectronics.com Kalle Hyvönen

      I’m always waiting for Dave to say “tilting bale” when he starts saying something “tilt..” cause it has to be one of the most used words on the vlog :P

    • http://N/A JDG

      Add me to the list with a 205B. One bad cap, swapped it out, another 2nd monitor for watching the EEV Blog in the background.
      Time to spend some of my hard earned cash on a good ESR meter.
      Any suggestions under a few thousand $$$?

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    • Gerd G

      I repaired a Philips TFT 170S5 last month. Bad CAPXON-Caps. No one was bulged! But ESR was high. And the 100uF/450V was the badest. This Cap was the fault and the Monitor runs after changing this Cap. I changed all Caps.
      It has system. The Philips 170S4 had a problem with the EEPROM on the logic board. It loses data.
      Greetings from Bavaria (Germany)!

      • http://www.eevblog.com EEVblog

        Another monitor saved!

    • http://www.eevblog.com Jan

      Anyway, if you want to buy a new TV-set or a new computer monitor, dont choose a Samsung. I am a technician, who can’t recommend this manufacturer.

    • Rick

      I useed to repair CRT monitors and they lasted much longer that flat panels. Shouldn’t be so.

    • http://RetroCable.com Karl

      Thanks Dave for the cap replacement tips, just done this type of fix on an LG monitor.

      Replaced 6 capacitors on the psu with low ESR
      it’s now working again.

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