Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fault?

[robzilla]

Hi guys, i posted over on Av Forums, but no luck.

Just by reading through some of the replies to other similar issues, i feel pretty confident one of you will be able to help.

SO here we go...

My Samsung LE40580C went black the other night while watching TV. It's less than two years old, but out of warranty.

Here is the issue:

Audio Works
Backlight is on - its still black, but in a dark room you can see it's on.
No video
All capacitors look okay

When i lightly tap the screen, it goes white for a bit then fades back to black - so back light is def on.

Any thoughts? I opened the back up and everything looks fine, nothing burnt or leaking.

T-Con?
Av Board?
Powerboard?

Any help narrowing it down?

If the speakers are working and the backlight is working, surely it cant be the power supply?

If the AV board is picking up a signal that should be okay as well?

Does that mean it's likely the T-Con?

I got a quote from the Samsung TV repair people, gave the symptons over the phone and they seems to think its the power supply? But want £250 to fix, where i can buy a power supply board and swap it out for £35...

Many thanks all, i trust you will be more helpful than Samsung Support.

Thanks
Rob

[tom66]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

T-con most likely - these boards have a fuse on them which can blow with or without an actual failure on the T-con. It is a fairly common issue with Samsung LCD TVs.

What a load of bollocks (excuse my language) - £250 to fix a 40" LCD TV? You can get a new one for £300! Besides, it is unlikely to be the PSU as you said, you have backlights and sound.

[robzilla]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

Awesome, thanks Tom. I'll take off the t-con cover tonight and get the model number.

Yes the repair costs are criminal. This was from the Samsung authorised place, noone else wanted to touch it. I have found a T-Con for £25 so its 1/10 the price!!

I'll order tonight and post results!

Rob

[tom66]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

Awesome, thanks Tom. I'll take off the t-con cover tonight and get the model number.

Yes the repair costs are criminal. This was from the Samsung authorised place, noone else wanted to touch it. I have found a T-Con for £25 so its 1/10 the price!!

I'll order tonight and post results!

Rob

You can replace the fuse on the T-con. Let me know if it is blown (you can check with a DMM if you have one, if not Maplins sell one for £5 which will work fine.) If it is, I have some 4 amp SMD fuses here, which are the most common fuses on these T-cons, and you can have one for the price of postage...

[robzilla]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

Awesome - i got a maplins down the road. I'll pick up a dmm there - i'm expat'ing over here so all my gear is back in Aus.

I have attached a pic of what i have read is the t-con. The bit pointed out in red is the SMD yeah? Can i just pop it off?

[tom66]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

That's the fuse. You will need to desolder it.

I do it by applying a bit of solder to each end of the fuse, then slowly pushing on one end with the soldering iron. The fuse will come off easily.

If you don't have a soldering iron Maplin sells those too (you'll need some solder too (lead-free is fine)) I think it was about £10 last time I got one in an emergency, but if you're looking at £15 for tools, when you could just replace a £25 board it might not be worth it. Unless you start getting into the hobby of repairing them, like I did.

[robzilla]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

haha i must admit, the fixing of it has become more interesting that the actual TV watching!

I DMM'd the fuse and i had current running through it so it was fine, so i guess it wasnt the fuse.

I managed to get the T-con from ebay for £12 posted. Hopefully it works!

I'll keep you posted and thanks heaps for the help so far.

[tom66]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

How did you check the fuse - did you use the ohms range of your meter?

[robzilla]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

Yep, dropped the ohms to the min value, then tested. The dmm went from 1 down to .000, so i'm guessing that means resistance is zero (which means that the fuse is still intact?)

[tom66]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

Yep, fuse is good. Try the new T-con and if that doesn't work more detailed troubleshooting can be done. But I think it will work.

[robzilla]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

Hey hey hey, all fixed. I got the replacement tcon in and its working again!!!! And Samsung wanted a few hundred quid...

Cheers Tom, much appreciate your help.

[senndogg]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

keep the t-con! another user in this forum may troubleshoot it! (maybe a failed voltage regulator i think or dc-dc booster).

[tom66]

Re: Samsung LE40C580 - Audio working, backlight working, no picture. Help diagnose fa

keep the t-con! another user in this forum may troubleshoot it! (maybe a failed voltage regulator i think or dc-dc booster).

Yes, failed T-con are very useful and a challenge to debug (no schematics!) Put it up on eBay for 99p if you want, someone may buy it.

Glad to hear you fixed it!