Samsung t260hd no power led

[awdark]

This one has me scratching my head

TV does not respond to remote, power button, and has no standby LED.

The TV does light up the toslink port.
I measured the rails, 15v and 5v (x2) are surprisingly okay. I'm actually surprised the rails were active, how does it know it is on I thought typically there are standby always on and the rest were switched?

Probed around the main board and everything labeled corresponded to the right voltages. The LED for standby did not report voltage, but the IR receiver does have 3.3v

USB flashes once but isn't active.

Any suggestions? Feels like the main board or maybe the remote/touch switch?

[awdark]

Re: Samsung t260hd no power led

Adding photos of power supply.

I have tested the voltage for the 15, 5.2, 5.2 lines both connected and disconnected from the main board. Everything seems solid. I don't know how to test the other pins, and I have a feeling pin 9 (on/off) is a logic pin for the back light.

The main board has several test points on the back and almost everything reads 3.3v or higher.

[Moreno83]

Re: Samsung t260hd no power led

Just an idea:

On Philips tv's you can disable/turn off the front led. Don't know if samsung has the same option , that might explain this.

You don't have any sound?

[martyparish]

Re: Samsung t260hd no power led

What's the voltage on ON/OFF pin?(while pressing power button)

[ReeceyBurger123]

Re: Samsung t260hd no power led

Check this fuse, commonly blows for no reason.

[awdark]

Re: Samsung t260hd no power led

Just an idea:

On Philips tv's you can disable/turn off the front led. Don't know if samsung has the same option , that might explain this.

You don't have any sound?

No sound no picture.

What's the voltage on ON/OFF pin?(while pressing power button)

ON/Off pin disconnected from main board almost zero.
Connected to main board almost zero (roughly 0.019).
Pressing power does nothing.

Check this fuse, commonly blows for no reason.

Thanks for the tip. Did not notice that fuse. Fuse is okay.

------------------------------------------------------------------
Did more testing while it was open.

Checked power supply more - I noticed a cloudy film on the metal backing near the fan7602b chip. That and the power mosfet are probably abused, a bit heated but otherwise functional otherwise I don't think I would get the 15v, 5v, 5v lines.

IR sensor is working, data pin goes low when I press button on remote.
"Key 1" button is working I see it drop from 3.3v to 0 when I press the touch button.

I'm guessing this just all points to failed main board.

Including a few sharper pictures for future reference. Felt bad about my first few.


If the main board is bad. Are there any suggestions on a LVDS controller? I see it has a chimei_M260J3-L01 but I don't know how easy it is to find a compatible controller.

[dick_barton]

Re: Samsung t260hd no power led

On your first picture in post #6 it shows Q101 with one pin not soldered or at least poorly soldered. Have you resoldered that pin since taking the photo.

Do the backlights come on momentary when you come out of standby?

What is the model number of your power supply?

[dick_barton]

Re: Samsung t260hd no power led

Ebay seem to advertise a lot of Inverter transformers for this model. May be worth your while checking the resistances across each winding.

[awdark]

Re: Samsung t260hd no power led

In terms of back light the TV does absolutely nothing. Like no standby LED. No attempt to show any signs of life when pressing power. The only light I can see is the LED from the toslink on the back.

Yeah I had taken q101 out based on a guess and a similar post. I didn't really reinstall it back too well because I was planning to take it out again. My initial guess was that part failed because I saw a similar TV here with that issue and the part on my power supply had a thin film of something on it making it difficult to read. I was able to rub it clean with my finger but I ordered the part before I tested all the voltage rails.

Does anyone know the logic pins for the Samsung power supplies? Now I'm curious to find out if the on/off logic pins should have voltage.

[dick_barton]

Re: Samsung t260hd no power led

I don't know if this schematic can help you.

[fpltdc]

Re: Samsung t260hd no power led

Were you able to eventually fix this? I have the same problem with my T260HD as it will not power on and the only light I see is at the toslink in the back. New batteries in the remote control will not do anything and I get no response whatsoever pressing anywhere at or near the bottom right corner where the "power button" is supposed to be. I have already opened it up and I couldn't find any suspicious-looking caps on either board and both ceramic fuses seemed to be in working order - I missed the F301 fuse though and will check it again. My electronics knowledge/expertise is extremely limited so I could really use any help. I have seen some power boards (IP-58155A/BN44-00226A) on eBay as well as the inverter transformer but I'm more inclined toward getting the whole power board as it is already in the $28-38 range but I hesitate until I can know for sure that it is indeed the cause.

[fpltdc]

Re: Samsung t260hd no power led

I was able to find some of these files that I suppose are for the service manual. I tried to follow the troubleshooting guide for the "No Power" section and as far as I can tell, I got 15V at pin 2, 5V at pin 6, and nothing at pin 7 at CN100, so I guess the problem is at the IP or power board. I probably will go ahead and buy the board on eBay since I am not that good at all with soldering/desoldering, especially if they are the tinier components (bad eyesight and shaking hands), although I may still try to troubleshoot the power board further before then.

[dibsrepair]

Re: Samsung t260hd no power led

Read "4Troubleshooting.pdf" in "https://www.badcaps.net/forum/showpost.php?p=677215&postcount=12" to id which board causes the issue.

Mainboard was my issue. Ordered the last one that is out there in world wide web. Also ordered the "SEMS10 IC"(Big main Processor 280+ legs). Will attempt to fix the old board. PM me if need a mainboard.