Samsung un49mu7000f dead no power

[lotas]

Do you have Neoprogrammer or AsProgrammer?
Can I see a photo of the programmer log?

To remove protection before erasing the chip, this means unchecking all the checkboxes and pressing write.

[steven91919191]

IT WORKSSSS! Thank you sooo much. I really appreciate your time!

[lotas]

IT WORKSSSS! Thank you sooo much. I really appreciate your time!

Ok!

[Marol]

Hello everyone,

I have exactly the same issue with my TV.
Could someone please take a look at my dump?

[lotas]

Hello everyone,

I have exactly the same issue with my TV.
Could someone please take a look at my dump?

Your dump is OK, working. What is the status register in the dump, what does the programmer show?

[Marol]

Now I can’t tell you the original values anymore because I tried other dumps, but of course without any result. I have a T48 programmer. From what I understand, I need to set S7, S3, S14, and S9, right?
Do you think that if I flash my dump onto a blank chip and set the correct bits, it should be work?

[lotas]

Now it is clear, the dump must be original, that is, the software version must match the eMMC software version, if it was the original dump, then try to write it to the native spi flash and after writing, install and write the status register (0x88, 0x42)

Status register: 1
S7 (SRP0)
S3 (BP1)

Status register: 2
S14 (CMP)
S9 (QE)

[Marol]

Maybe I should describe what happened. The TV would not turn on, no red standby light. Just like in the other case, the power supply had 9V instead of 13V.
I have another almost identical TV, but with a different panel. I measured the mainboard using the diode test mode on my multimeter, and everything seems fine – I even compared it with the other board. That’s why I suspect the memory.

I’ve ordered a new memory chip; it should arrive tomorrow, and I’ll let you know how it goes.

By the way, can a corrupted 25Q80 dump also cause this kind of symptom?

[lotas]

9v is when the TV is in standby mode, 13v is when the TV has already switched to operating mode, if the indicator does not light, then the problem is either in the 25Q40 firmware or in the DC/DC converters, there have been cases due to the backlight (the backlight shorted to the case and the power supply went into protection, just disconnect the backlight from the power supply and check if the standby mode indicator appears) or the processor itself...
25Q80 is T-CON firmware, it has nothing to do with standby mode.

[Marol]

The chip I ordered came wrong 25Q40EW 1.8V. I used 25Q80JV which I had at home instead of 25Q40, set the bits correctly and programmed the dump you checked. Still no standby, nothing changed.
Have you ever tried such an experiment with 25Q80 instead of 25Q40?
Do you think if I buy the proper 25Q40 it will work?
I also tested PSU with backlight only – it lights evenly, looks OK. Thanks.

[Marol]

After programming an identical chip, the board doesn’t start up. I compared the voltage drops on the regulators with a working board, and everything looks fine. What would you recommend checking next?

[lotas]

When dismantling the SPI Flash, did you accidentally remove any nearby components (SMD resistors, capacitors?) Check the HDMI signal lines (8 lines on each HDMI connector) relative to ground; there should be no low resistance, as well as the LAN port.

[Marol]

Thank you for your help. Today I decided to reconnect the TV again, and something unbelievable happened... it turned out that all the voltages that were previously present had completely disappeared.

I started checking and found that fuses F202 and F203 were blown. Then I measured the voltage drops again and, to my surprise, I discovered that the 12V coil was shorted to ground. During a short-circuit test, a cracked capacitor (probably C303) started heating up.

I desoldered it, replaced the fuses with 0R resistors, and the TV came back to life. Do you happen to have the schematic for this board?

It seems the capacitor must have been intermittently shorting before, which caused the power supply to shut down. Earlier, the voltages on the board looked correct—I measured the drops twice. I also checked with a thermal camera and inspected under a microscope, but found nothing. And today, after just an hour, the TV is finally repaired.

[lotas]

Congratulations on your TV repair. I don't have schematics for modern Samsung TVs, and they're not even available at authorized service centers (in fact, they don't even exist), since no one repairs them, but replaces them entirely with a new board. Yes, ceramic capacitors are a common problem with modern technology.