Samsung 55HU8590 UE55HU8590 maybe one connect box ocb

[An-klamm]

Hello!

I have a TV that I can't get any further with.
It is a Samsung UE 55HU8590 with one connect box.
When I turn on the TV without the one connect box, the animation on the TV tells me to connect the ocb.
As soon as I connect it, the TV restarts (panel goes dark) and the TV tries to start continuously (relay on the SMPS clicks about every 3 seconds).
Since the TV works without ocb, I assume that it can't be the PSU?!
I have measured all contacts of the one connect cable against GND on the ocb board and there is no short circuit anywhere.
Is there something elese i can measure?
I already tried to heat and cool down the mainboards (in the TV and the ocb) but nothing changed.
I read somewhere that it could be the emmc or eeprom.
Is there any way I can verify this?
Especially whether it is the TV or OCB mainboard.

[An-klamm]

I bought a new OCB. Saw that the previous owner had it running. Connected it to my TV and now get sound but still no picture. When the OCB is connected, the background lighting stays off. But even with a bright construction spotlight, no outlines are visible. So it seems that the backlight is off AND no picture is displayed.

Any ideas?

[Diah]

at first time you have screen and BL with animation connect to COB., it tell the BOX defect or its cable. but you went to heat the MB and here are your mistake,,,, only you need
1- with out OCB did you have screen and BL again ? if yes... mean the box or it cable defect..... if NO screen or BL then you did BGA issue on MB during the heating.

[An-klamm]

Without the box i still get backlight and animation.

I only heated up to 40-50°C. I think this should not damage anything.

[Davi.p]

from a previous thread, seems to me a software problem in the main unit cpu board..

[An-klamm]

changed main board in TV with one i bought from aliexpress (made a few good expirences with this seller already) but same issue. So only the TCON and Panel are left.

[lotas]

Did you replace the cable itself with a known good one?

[An-klamm]

I replaced it but with one I bought from eBay. So I'm not 100% sure.

[An-klamm]

So you are all informed:
I tried another cable and everything works fine again.
So in my case there was a broken TV mainboard, a broken ocb and a broken cable.
The tv does not work with only one or two of this things replaced.

I assume the repairshop the TV was first brought to put all his defective parts in it and told the customer its not fixable.

[lotas]

Yes, most likely this was the case, it is mainly the connecting cable that suffers, since it is very fragile and is susceptible to frequent bends and kinks.

[An-klamm]

My TV is now running again but I have a defective ocb and a defective TV mainboard lying around.

I would like to repair this.
I have measured Vdrop on all major components and they are the same, so I think it is a software error. I have read out all winbond ICs with my CH341a and compared the files from the defective and healthy board. The files are exactly the same size and have exactly the same content.
there is still an emmc Samsung KLM8G1GEAC-C021 on the ocb.
I suspect that this emmc is defective (or has defective sectors). Can I somehow read it out without desoldering it?
I have an XGecu T48 at my disposal. But I don't see any pins around the emmc where I could possibly connect it.
Is it only possible by desoldering the emmc and getting a suitable adapter?

or could it even be a defective RAM (Samsung K4B4G16460-BCMA)? can I test the RAM somehow?

Is the RAM replaceable or do I have to program/link it somehow?

[lotas]

Do you have such an adapter for your programmer so that you don't have to unsolder the eMMC, but solder it to the board and read data from it? Have you ever gotten into reading or programming eMMC?
https://www.autoecupart.net/products...-3g-programmer

[An-klamm]

No, I don't have such an adapter. I have one for desoldered emmc's https://a.aliexpress.com/_EIw202z
I have programmed various microcontrollers but have not yet done anything with emmc's.

If the OCB wasn't so expensive, I would remove the emmc from the good one and give it a try.
If someone has the program, then I would unsolder the emmc from the defective OCB and solder a new one on. Can I get this program somewhere?

[An-klamm]

Is it possible to download the EMMC firmware/software/data somewhere?

[lotas]

Is it possible to download the EMMC firmware/software/data somewhere?

Your programmer (T48) supports this eMMC (Samsung KLM8G1GEAC-C021), will it be able to work with it?

[An-klamm]

Thats the supported device list for my programmer. (searched for KLM8G1GEAC)
I already ordered a KLM8G1GEAC-C021 (I dont know what the -C021 is for and whether its important or not)

I think I'll get around to putting the emmc (the one with -C021) into the programmer at the beginning of next week and see if it basically works.
Then I would get back to you and ask again about the content for the emmc.

[An-klamm]

So here I am again, reporting back.
Unfortunately, I didn't get to it earlier.
I have ordered a new KLM8G1GEAC-C021 and have been able to read it with the adapter (takes about 10 minutes)
If someone could upload the content for the emmc of a working ocb somewhere, then I would try to unsolder the presumably defective one and solder in a new one.

[An-klamm]

lotas do you have a dump or can you tell me where I can find it?

[lotas]

I'll see where it was from the HU9000.

[lotas]

I'll see where it was from the HU9000.

You can read your dump emmc, throw it into the cloud and give me a link, I’ll see if it’s alive or not.