Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

[Dannyx]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

I DID try the TV one more time after reading the dump the first time, since I also wiped and re-wrote the chip shortly after, but didn't know what to set in that sub-menu. No change in behavior.

I'm actually curious to see if I NOW get all FFs at the start too when I pull it off to read it again. What were the options that needed ticking in the sub-menu, assuming I write the original dump back ?

[lotas]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Try another clean dump 25Q40, after recording the dump, set and record the status of the register 0x88, 0x42.

[Dannyx]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Yes, just write it down.

Thank you for the effort, but no: no change. Same 2 flashes and not even a sign of life, with or without the panel connected.

[lotas]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Yes, just write it down.

[Dannyx]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Try this one (it has two different addresses from yours).

Do I just flash it or do I set some other options ?

[lotas]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Try this one (it has two different addresses from yours).

[Dannyx]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Here's the dump from 25Q80 and the panel model (I edited the picture by accident and cropped it weird, so I hope you don't need other info outside that).

[lotas]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

What panel do you have (number, model) and post dump spi flash 25Q80, maybe the problem is there too.

[lotas]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

TRDY1 -3 they are connected to each other (this is when there are two lvds loops) and if you disconnect any one of them, then you open the circuit and the controller sees that the panel is completely disconnected and the power stops flowing to the panel; with the jumper, the controller sees that the connections are connected two loops, this trick is for diagnostics.

[Dannyx]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

I have reasons to believe my dump might be OK after all, which sadly lowers the chances of this board being fixable. I compared my dump to others that had issues with similar TVs and noticed the corrupt dumps have empty bits up to 180, while the "fixed" ones essentially restore these bits. My dump on the other hand looks very much like one of the "fixed" variants, with no FFs in the beginning, so I'm starting to think this is a NAND issue or a CPU issue, which might also explain why it's not starting even with the TRDY pads jumped together.

I also wanted to work out how exactly this TRDY loop works and exactly WHY I had to do that in the first place, since I was a bit confused when I saw other videos of similar TVs where they just unplug one of the ribbons and the other half still works like you'd expect, even with the TRDY loop open, allowing you to at least narrow down the issue to one of the buffer boards and work from there with the scotch tape trick. This doesn't happen in my case, with or without the jumper wire. If I buzz out the first and last pins of each connector, sure enough, I get continuity with both ribbons connected and infinite resistance with either unplugged, so it makes sense. I think a pin on the CPU gets pulled high through this loop, like a simple switch.

[Dannyx]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

The inductor (inductor) can also be on GND, this is for converting negative voltage in relation to gnd, for VOFF = VGL = VGOFF = VEEG = from -5V to -9V.

Yes, I gave up on that idea - nothing wrong there.

[lotas]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

I believe you refer to these. They all read in the Mega-ohms range, except for those vias in-between, which are GND. Same goes for the USBs.

As I was buzzing around, I noticed this coil L406 reads short to GND (just my meter's leads worth of resistance). I tried voltage injection with around 0.8v which resulted in around 1.2 A of current flowing, but nothing got hot - at least not something that I could feel. It may be an inverted buck converter and the coil is connected to GND on purpose.

Picture flipped upside down on its own when I uploaded it for some reason, sorry about that....couldn't fix it.

The inductor (inductor) can also be on GND, this is for converting negative voltage in relation to gnd, for VOFF = VGL = VGOFF = VEEG = from -5V to -9V.

[Dannyx]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Check the signal line resistance for low or short circuits at the USB and HDMI connectors to ground.

I believe you refer to these. They all read in the Mega-ohms range, except for those vias in-between, which are GND. Same goes for the USBs.

As I was buzzing around, I noticed this coil L406 reads short to GND (just my meter's leads worth of resistance). I tried voltage injection with around 0.8v which resulted in around 1.2 A of current flowing, but nothing got hot - at least not something that I could feel. It may be an inverted buck converter and the coil is connected to GND on purpose.

Picture flipped upside down on its own when I uploaded it for some reason, sorry about that....couldn't fix it.

[lotas]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Check the signal line resistance for low or short circuits at the USB and HDMI connectors to ground.

[Dannyx]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Connected incorrectly!

Ok, let's try it again...sure how that first pad didn't kill anything (else) Same behavior sadly, even when moving the wire to the pad you indicated.

[lotas]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Connected incorrectly!

[Dannyx]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

Ok, I'll provide as much info as I can in one go: connecting those test points together did not change anything (I HOPE I got them right, especially since the bottom one isn't marked, but I inferred from other posts it's pin 1 of the LVDS ribbon). The set still doesn't go past blinking the LED, no matter if one/both/neither of the ribbons are connected.

Next: I pulled off and read the 25Q40 IC and got THIS. I tried ASProgrammer just to see what it's like, since I haven't used it before. It appears to read the chip alright, so it's happy with my cheap and cheerful CH341. I don't know what to do next though. I read something about setting some registers, but don't know how to do it or if that alone is enough. I clicked through the different options and came across this "SREG" screen which seems familiar (definitely saw it mentioned in another post), but most of the fields are blank, with all blank boxes ticked on the rightmost column, so I can't read what they are. I tried it on an older win 7 machine just to make sure it's not a compatibility issue, but the same thing happens.

[Diah]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

you still a live ..lol

[Dannyx]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

It’s more likely that the issue is not in the firmware (25Q40), but in the panel, first you need to install a jumper between the FB_TRDY_1 and FB_TRDY_3 contacts on the motherboard, then you can check each half of the panel, disconnecting one lvds cable at a time

Thanks, it's a start - hence why I said I'm no longer up to date with all these "tricks" Ok, so I just run a wire between them them like that ? That's wild I assumed they'd be adjacent solder pads I'd have to bridge for each side of the panel

[lotas]

Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)

It's more likely that the issue is not in the firmware (25Q40), but in the panel, first you need to install a jumper between the FB_TRDY_1 and FB_TRDY_3 contacts on the motherboard, then you can check each half of the panel, disconnecting one lvds cable at a time