Dead Samsung 46" LED (model UN46C6300SFXZA)

[mmartell]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

Good job George.

[freakaftr8]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

Good to hear George! And kudos for going the extra mile and pulling the panel to check the LEDS!

[Jidis]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

freakaftr8-

Got it! Got it! -Thanks!

I probably didn't push hard enough. There's a point where they look like they're in, but they can go a little further. I also cleaned the contacts while they were out.

BTW- If anyone should ever hit this thread on a search, something does in fact appear to have changed from the information in the Fast Track Troubleshooting Guide,etc. First thing I did when the power board was in was to power it up with no mainboard just to verify that the lights now worked, and it did nothing. The backlights didn't come on until the rest of the connections were made. Again, this is an "A" version of the PSU board, so I'm not sure if that info works properly on the original "B" board, or if maybe somehow they were just wrong about this particular set.

So glad to have this up, and thankful of all the help I got here. I've got a whole new pile of electronics videos in MP4 format that I can now watch on a nice big screen.

George

[freakaftr8]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

I see them. Reseat LCDs cable. The one that goes from mainboard to tcon

[Jidis]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

Hope this isn't bad news.

New PSU board (BN44-00356A) showed up today to replace suspected dead PSU (BN44-00356B). Set now powers up and works, but I got thin vertical green lines across the whole screen. I reopened the set and reseated all ribbons to the T-Con board, and ran it again (with the back off). This time, it's covered with red vertical lines.

This picture's probably not the greatest, but it looks like the sort of image you get when you watch a video with a not-so-fully-supported codec.

Does anyone have any pointers or could there possibly be a setting somewhere that's off?

Thanks!

George

[budm]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

Yes, three AA and 470 Ohms which will allow the maximum current of around 10mA.

[freakaftr8]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

I used a fluke meter and yes it has enough to light the led forward bias. But true most do not. I would try the battery trick before a power supply.

Budm would you suggest 3 double A batteries and a 470ohm resistor?

[budm]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

Most DMM does not put out enough voltage to turn on the White LED, it needs to be able to put >3V to forward bias the White LED. Using 3V~4.5V batteries with 470 Ohms resistor to limit the current for testing each LED will be better.

[Jidis]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

What do you guys think of ordering every single active part that's on this thing from Mouser or somebody? If there was a dead something on there, I'd pretty much have to hit it that way. It would probably run about six bucks.

I may start poking all the passives today just to see if anything looks bad. Those long high voltage electrolytics were all I really looked at before.

George

I found when testing LEDs with a voltmeter in diode check mode even if the led lights up also note what the meter is reading g at the same time. Somewhere in the range of 5kohms is normal i think. If a reading is different suspect a bad led. Even if it lights up.

The only diode check functions I've had on stuff here wouldn't light an LED, but they will give you some resistance reading in one direction. That's interesting though. What meter is it?

[Jidis]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

It seems to be about the cheapest of all the boards for this thing.

Damn, I thought I was good to go on that BuyQual place someone directed me to. Looks like their shipping charge is almost the price of the board, then you'd probably have to pay it again if anything didn't work.

I see "repair kits" for the various Samsung power supplies all over eBay. I wonder if that's an indication that someone actually has a good idea of what croaks on these particular boards. The only pictures look like two or three regulators and a few smaller caps, but I'm not sure if that's the actual kit contents.

George

[freakaftr8]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

I found when testing LEDs with a voltmeter in diode check mode even if the led lights up also note what the meter is reading g at the same time. Somewhere in the range of 5kohms is normal i think. If a reading is different suspect a bad led. Even if it lights up.

[Jidis]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

You could have got a faulty PS wouldn't be the first time. I would try another before going back in the panel and double checking the leds.

Thanks mmartell, I probably will. It seems to be about the cheapest of all the boards for this thing.

George

[mmartell]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

When I pulled my strip again tonight to look for an open led I found all leds to be lighting. Scratched my head for a minute then devised a new test. Instead of putting the leads on either side of the led I put one on the NEXT led just across the small gap between them since they are in series. This way I could test the led AND the connection between them. Sure enough I had a dead spot between two leds.

Had what looked like corrosion or contamination of some sort. May have happened when I had the strip pulled from an earlier repair but can't say for sure. One of those leds also happened to be dim so I replaced it and wired in a jumper.

You could have got a faulty PS wouldn't be the first time. I would try another before going back in the panel and double checking the leds.

[Jidis]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

Well, I don't know if this is good news or bad for me, but I appear to have two hundred and fifty-six nice healthy white lights. I probed each and every one with 3.3VDC through a 470ohm resistor.

So who's the suspect now, the PSU board?

BTW, ShopJimmy finally got back with me and said the same thing about unplugging CN201 from the main to see if the lights worked, and that it was the power board if not.

Let me know what to do, and again, you guys help has been awesome.

George

PS- That was some stressful s*#@! Hope I don't have to go through that again (and that I got the thing back together properly ).

[mmartell]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

Ya I did it face down so I wouldn't have to mess with the layers or disturb the lcd panel itself and remove only the part I needed. A little tougher probably, but doable. Only the diffuser (taped to the led strips) comes up with the back plate if you're careful.

[freakaftr8]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

Actually let me clarify.. Everything needs to be free and clear from the panel as in the panel should be ready to lift out when you tape the carriers to the screen.

[freakaftr8]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

Then of course start removing the 1000 (exaggeration) or so screws from the metal frame surrounding the LCD panel but remove the black bezel first that's clipped in.

[freakaftr8]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

yes you should be face up now. Tape the carriers (the two delicate boards connected to the LCD to the screen after you flip it around).

[Jidis]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

I'm halfway in this thing now. Thanks mmartell!

The bezel and frame are now off. I'm gonna break for a bit to eat, and get back on it very slowly to keep from screwing anything up.

There are clips around the edge on mine, but I'm wondering how I need to approach things to safely get to the light strips. It's got those two fragile looking long thin PCBs hanging off the bottom which connect to the T-con board. Do I lay it face down, unsnap all the clips and lift the bulk of it away from the glass/screen part?

Thanks,

George

<EDIT> freakaftr8's instructions are now making a bit more sense to me, but I can't tell if he's still got the panel face-up at the point I'm at now.

[mmartell]

Re: Dead Samsung 46" LED (model UN46C6300SFXZA)

Sounds like a microfiber cloth and distilled water would do the trick.