[SOLVED] Forced "toggle" to repair bricked TV?

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dssenceme
Posts: 5
Joined: Thu Apr 17, 2014 12:46 am

Re: [SOLVED] Forced "toggle" to repair bricked TV?

Post by dssenceme »

To OP
Hi sorry I just private messaged you , but I need help from all your knowledge. I see you're quite knowledgeable with eeprom debugging and engineering. My story is as follows I got a un46d7000 Chilean model. My mainboard it's a BN94-05226H this tv initially worked flawlesly. But for some reason It got an ac discharge on the hdmi ports, as I interconected different devices and one had some live AC going through the gnd shield, so it blew all hdmi ports.
Tv kept working but without HDMI funcionality , the IC from silicon image which managed all the hdmi interoperability got blown. so VGA and RGB RCA composite worked. After some time something odd started happening whenever the elctricity went off , and then came on . I switched the tv turned on fine.. but randomly like it clicked and turned off.. this many times until it steadied and kept working. I never quite gave this much attention.. but once more electricity went off .. this happened again but then the tv didn't start anymore.
So I went through many forums and came up from a thread on badcaps from a guy with asimilar experience where the tv clicked and then shutted of and was the led strips on the tv which were shorted. I dissasembled mine to check the led strips but they were ok. I force the led strips to turn on by bridging A5v on the power connector from the power supply with Pwm1 to pwm4.
I even managed to get a new power supply but the tv again turned on .. clicked and off.. backlight didn't even come on. just the clicking.
So I started reading about eeprom corruption.. this tv I never upgraded it's firmware. I know the tv runs some kind of linux flavor maybe propietary. So from your theread I supposed something might have happened internally that made some boot up process start to cycle the kernel.. that's why the tv doesn't initalize and does the clicking sound.
I read about a guy saying to switch partitions or toggle partitions so that the tv comes to life again. But .. I don't know how to reverse engineer the eeprom data.. which binary bits to alter. I have an eeprom programmer and managed to dump the main eeprom data. and I'm about to dump the micom data as well. If you can guide me we could figure out what's going on. I have a digital osciloscope , digital meter, eeprom programer.
I was starting to think this tv suffers from the same type of corruption samsung cellhpones do suffer as well causing sudden death. Maybe it's all inter related I read about the eMMC bug. A friend of mine has a box called RIFF box which is used to resurrect samsung and many other phones by tampering with the JTAG connector. I was thinking we might as well could connect through the JTAG port of the mainboard of this samy tv , and go straight into the contents of the linux directories and edit the scripts as needed to avoid this loop lock up, again I'm not savvy into this like you but I have done similar stuff before. What's worse I tried searching all over the net even on russian forums for service manuals and datasheets to see if anybody has managed to go this deep through JTAagging to resurrect this locked up board doing the clicking due to corrupted eeprom and came up with nothing.
So again I don't want to bother you.. but I know you can be of huge help to me. I've never entered to the service menu of my tv so Serial debugging I don't think it's enabled on my mainboard. What's worse I don't see an exlink connector soldered. but I do see there's the pinouts for Tx and Rx.
Forgot to tell you I have a spare BN94-04355J mainboard I bought to remove the hdmi chip so I could solder it to my board. This board has the exlink port and there's a MP222EC IC which is in charge of translating the signals into RS-232. So I could try desoldering that chip and soldering it to my original mainboard to see If I could at least get serial console debugging to reset maybe the eprom.
Some points I didn't tell you. I alredy tried resetting the main eeprom with SDA to GND , SCL to gnd , SCL and SDA , Mreset to SDA with no results. I also desoldered the eeprom and soldered a blank atmel eeprom to see if it regenerated the eeprom data but it didn't fill it at all so I think the tv it's by some way or another locked up.
I soldered some wires to the back of the board to SDA SCL and GND from the micom chip . I bridged SDA and SCL and the tv started with backlight on.. I think there was some noise on screen but nothing no menus nothing. So that makes me think the tv it's locked by some way.
So my question is , should I desolder the micom , the eeprom ? what should I do. I 'm kind of lost here. If I could get serial console access that would be great but I don't know it would be posible as I haven't enabled it .
I'm leaving you the pictures here. Don't know why but pictures are not stretched properly . You can check the url links instead.

sbav1
Official SamyGO Developer
Posts: 374
Joined: Fri Jan 15, 2010 10:20 am

Re: [SOLVED] Forced "toggle" to repair bricked TV?

Post by sbav1 »

dssenceme wrote: I've never entered to the service menu of my tv so Serial debugging I don't think it's enabled on my mainboard. What's worse I don't see an exlink connector soldered. but I do see there's the pinouts for Tx and Rx.
Forgot to tell you I have a spare BN94-04355J mainboard I bought to remove the hdmi chip so I could solder it to my board. This board has the exlink port and there's a MP222EC IC which is in charge of translating the signals into RS-232. So I could try desoldering that chip and soldering it to my original mainboard to see If I could at least get serial console debugging to reset maybe the eprom.
Soldering MAX223 IC from different mainboard alone would be not sufficient, it will require (at least) a bunch of some additional SMD components to work (not to mention the wrong UART service menu setting). Not worth the trouble, especially considering that you most likely have essentially the same signal (only 3.3V/TTL level, NOT regular RS232 +/-12V) on VGA connector.

If you are determined to do so, you can still get access to SDP serial console without this IC, and regardless of the UART/debug settings in service menu: Genoa SoC RX & TX (3.3V TTL level) are available on HC4052 analog multiplexer IC pins (I don't know which pins precisely in this model, but there are only 3 or 4 TX/RX pairs to choose from, see 4052 datasheet). However, I doubt serial console access would be all that useful for anything in your case - at best, it may (just may, if you're lucky) help you a little to establish what's wrong with you mainboard.

hedak
Posts: 81
Joined: Wed Jan 08, 2014 9:21 pm

Re: [SOLVED] Forced "toggle" to repair bricked TV?

Post by hedak »

@dssenceme
First i propose to create a new thread for your problem.

I have no D series experience so far, but are you sure that there is no exlink plug or something available? In my case it is within the vga plug.
(IIRC i got the watchdog bit in my C7700 SoC EEPROM bit changed via I2C access.)

@devs
Do D series tv's typically have a working second partition set by factory (as my tv had)?

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juusso
SamyGO Moderator
Posts: 10124
Joined: Sun Mar 07, 2010 6:20 pm

Re: [SOLVED] Forced "toggle" to repair bricked TV?

Post by juusso »

@hedak
no.
LE40B653T5W,UE40D6750,UE65Q8C
Have questions? Read SamyGO Wiki, Search on forum first!
FFB (v0.8), FFB for CI+ . Get root on: C series, D series, E series, F series, H series. rooting K series, exeDSP/exeTV patches[C/D/E/F/H]

DO NOT EVER INSTALL FIRMWARE UPGRADE

dssenceme
Posts: 5
Joined: Thu Apr 17, 2014 12:46 am

Re: [SOLVED] Forced "toggle" to repair bricked TV?

Post by dssenceme »

@hedak , and @juuso guys I started a new thread with my problem so you can help me out

viewtopic.php?f=23&t=7603

so many thanks !

Oeli
Posts: 6
Joined: Sat Sep 21, 2019 11:14 am

Re: [SOLVED] Forced "toggle" to repair bricked TV?

Post by Oeli »

Sorry for responding to such an old topic, but i am trying to fix my UE37D6200. (Started this thread a while ago: viewtopic.php?f=24&t=12982)

Now I found this topic which seems to contain much information which could be useful for saving this TV.
But the post containing the important instructions (viewtopic.php?f=23&t=5042&p=38840#p38840) contains dead links. Can anyone give me the missing pieces for solving this puzzle? Thanks in advance!

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