Samsung UN39EH5003FXZA won't stay powered off

[nomoresonys]

Re: Samsung UN39EH5003FXZA won't stay powered off

See if it will take another firmware/pairing update.

[Hannibal_Hector]

Re: Samsung UN39EH5003FXZA won't stay powered off

Yes, I just did another firmware update and it went through its paces, and there is no change. Still won't stay powered off.

[Hannibal_Hector]

Re: Samsung UN39EH5003FXZA won't stay powered off

Some further troubleshooting and a possible workaround.

I traced the PSON line on the mainboard to an NPN transistor that grounds the line when it receives about 1V to the base. I also traced the PSON line to an SOT23 voltage detector IC via a resistor (guessing to calibrate when it should enable), whose output goes to the MCU reset line. Its actually labeled on the PCB.

I am able to turn off the TV by either grounding the PSON line to turn off the PSU, or by grounding the MCU reset line, which then enables the NPN transistor and turns off the PSU. While the TV is 'off' it is not in standby, as it does not blink the LED when presented with IR pulses from the remote.

All of this suggests this circuit is working as expected, right?

While I am next thinking about monitoring the EEPROM lines with a logic analyzer to see what I can learn, I am also pondering a workaround to this power off problem.

Since this is not a client TV, the easiest 'fix' is a power strip... but since this IS purely for fun, I'm thinking of using an ATTINY85 to detect the remote power button IR signals, and control the NPN transistor on the PSON line. I can easily hide this inside the TV... What do you think!?!?

[Diah]

Re: Samsung UN39EH5003FXZA won't stay powered off

before we diving in Diy work. did the set saved the channel scan after replacing Soc 16 chip ? if no change
why dont try to replace the Soc8 slave eeprom !

[Hannibal_Hector]

Re: Samsung UN39EH5003FXZA won't stay powered off

@Diah... The channel scan was being saved even before I tested the Soc8 eeprom. So everything on the TV works, except it will not save the last channel selected, the volume, the input labels, the picture/sound settings, and even the Hotel mode settings won't save.

When I remove the Soc8 eeprom and read the contents, I can see the channel scan labels. This eeprom is working, because I was able to wipe it clean, verified it was wiped, and then reloaded it, and verified that. So both Soc8 and the new Soc16 eeproms are good.

Since I posted last, I've been thinking about the behavior of the SOT23 voltage detector. As I understand this circuit, the voltage detector monitors the state of the PSON line, and if it drops below a certain value, the OUT goes low (0V) to suspend/reset the MCU. Once the voltage is sufficient, it should go high. When the TV power cycles, I should see the OUT of this detector drop to 0V (active low), and then I should see it go to about 3V when the TV is running. But I don't.

As I understand this circuit, the NPN transistor is what the MCU (I am guessing its the MCU) uses to ground the PSON line and power off the PSU. Then, the voltage detector is used to actually monitor what the PSON line is actually doing... Did the PSU actually turn on/off? Is this an accurate assessment of what is going on here?

[Diah]

Re: Samsung UN39EH5003FXZA won't stay powered off

well i am guessing depending on what you wrote before.. this was before update the firmware...

. think then the TV self-shutdown with the melody. When I powered back up (melody), it would show the channel selected on the OSD and after a couple of seconds, it self-shutdown (melody).

and about saving this...

Coincidently, I’ve also noticed the the TV will not remember any settings, other than the channels scanned, after it power cycles. So for example, I can watch TV, select channel 2, change the name of the HDMI source to ‘test’, and when I power-off (melody), it reboots on its own (melody), and the channel is 41, and the HDMI source name is lost. All settings always reset.

as its strange.. because before update it was self shutting down and you self powered it on... all about yours calculation on PSON signal and NPN Transistor passed not with fact.

so are you sure downloaded firmware for exact model LOL

EDIT: since you are not Org. owner of this TV. so take look on the service manual i attached here.. need to compare the value of service menu, also could be yours set working as shop mode. which start on UHF channel 41 and always on.

[Hannibal_Hector]

Re: Samsung UN39EH5003FXZA won't stay powered off

@Diah, yes what you quoted is completely consistent with what I am saying... does not save, " other than the channels scanned..."

Before the update, I wrote:
"if I removed the antenna, I could power on, stay on and navigate the menu, select HDMI and the TV would display the HDMI video source including audio. I even got the unit to display video off the coax if it was standard def (from an old Tivo). As soon as I tried HDTV from the antenna, it self-powered off, never showing any video."

So again, completely consistent.

Also, the original owner said the TV would randomly NOT turn on, which I never experienced. I suspected that the original owner never realized that the TV wouldn't stay powered if the TV detected video. But, I really cannot trust anything the original owner said, just based on my personal assessment of speaking with them for 20 minutes and recognizing they are not capable of understanding what the TV was actually doing.

I have upgraded and downgraded the firmware several times and it has always behaved consistently.

I cannot get into the service menu, because the TV won't stay in standby, but this Service Manual isn't for my TV. I have the UN39EH5003FXZA and this Service Manual is for a newer model series.

Thanks

[Diah]

Re: Samsung UN39EH5003FXZA won't stay powered off

what is the chassis No ?
service menu can access also from power on state ( info --Factory ).. there are apk for samsung to inter service menu via any mobile with IR sender.

[vinceroger69]

Re: Samsung UN39EH5003FXZA won't stay powered off

service remote apk link here
https://wiki.samygo.tv/index.php?tit...%2B3SPEED_keys

[Hannibal_Hector]

Re: Samsung UN39EH5003FXZA won't stay powered off

Sorry for the noob question, but where is the chassis number, and is it labeled as such?

I am working through what I need to send the IR codes. Looking for phone or some such to do it with.

Also, to tie up a loose end: The voltage detector is mainly monitoring the standby (always-on) 5V line. Yes, there is a resistor from the PSON to the input of the detector, but the detector is primarily seeing the 5V line. Therefore, it makes sense that it isn't budging on the reboot, and I am now satisfied there is nothing wrong with this.

[nomoresonys]

Re: Samsung UN39EH5003FXZA won't stay powered off

Aren't these mainboards pretty reasonably priced to replace?

[nomoresonys]

Re: Samsung UN39EH5003FXZA won't stay powered off

Maybe that one will work, they want 44 bucks tho: https://tvpartsforsale.com/product/s...1a-main-board/

[Hannibal_Hector]

Re: Samsung UN39EH5003FXZA won't stay powered off

Ok, so life happened and I was just able to get back to this today.

Yes, replacing the main board is quite likely to fix this, but there's little fun in replacing the whole board. Not a lot learned from that so its really a total last resort, maybe. lol

I just built an Arduino IR blaster and used this code to send INFO > FACTORY: https://github.com/ironman977/SamsungIRRemote

This popped up the factory stuff, and I did a Factory Reset. Unit shutdown and then auto-powered back up. But, the problem persists. It will not stay off/standby.

I didn't try the FACTORY+3SPEED option. Is there anything in there?

Thanks again for sticking with me on this!

[Diah]

Re: Samsung UN39EH5003FXZA won't stay powered off

good job with Arduino .. i advice you to compare the value at service menu.. post photos how much you can on the value you have to see it..

also you try to change one value ( not critical one ) to see if it saved.. to exam the responsibility of the soc 8 on it.

[Hannibal_Hector]

Re: Samsung UN39EH5003FXZA won't stay powered off

I have a fallback plan that gets the TV fixed, but I am not prepared to call this done yet. I ordered a used mainboard off eBay for $20 and it works. The TV behaves. But, this is a last resort!

Attached are the settings I hope are relevant. I tried to make a change, like the Auto Power setting but it just doesn't save. (Is there a 'save' option I missed?) Also, since I have a working mainboard to reference, I dumped the 24512 eeprom from the working board and uploaded it to the faulty mainboard, hoping it might be corrupted. No change... behaves exactly the same. I also tried to disable the Watchdog without success.

So I still have the TV in pieces, because I'd like to fix the bad mainboard if at all possible. Any ideas?!? I picked a real head scratcher!

[Diah]

Re: Samsung UN39EH5003FXZA won't stay powered off

there are no save. any change will be active at next start,
yours photo https://www.badcaps.net/forum/attach...4&d=1616707728
the last one "power on opt" change it from "last option" to standby. if it didn't work then the I2C on chip fault need empty one to write it with dumps you have.

[Hannibal_Hector]

Re: Samsung UN39EH5003FXZA won't stay powered off

@Diah... brilliant minds think alike, lol. After I posted the photos, I remembered I'd ordered new 24512 eeproms and even before I saw what you wrote, I replaced it, using the code from the known good mainboard... and the result proves the original 24512, even though I can re-program and verify, is faulty!!! Programming the new one with the original code results in the same failure mode, strongly suggesting corrupted code. And re-programming it with the known good, makes it work again.

This is where I am now:
TV is running on the original main board, with a new 24512 eeprom, programmed with the replacement main board eeprom code. The TV is finally going into standby, and it remembers the settings! However, I think the code is different enough that there is a new issue. The TV will not allow me to select Antenna > AIR. It only allows Antenna > CABLE and if I try to select AIR, it will sometimes lock and turn-off, or just plain not save the setting. I tried factory reset too.

Talk about close!!!

[Diah]

Re: Samsung UN39EH5003FXZA won't stay powered off

The TV will not allow me to select Antenna > AIR. It only allows Antenna > CABLE and if I try to select AIR, it will sometimes lock and turn-off, or just plain not save the setting. I tried factory reset too.

Talk about close!!!

its sound to me the content of the Soc16 Master EEPROM early you replaced it didn't match the Soc8 slave one. try put back the original Soc16 in place.
or could flashing firmware again help too

[Hannibal_Hector]

Re: Samsung UN39EH5003FXZA won't stay powered off

The TV is FIXED... and I will let you all know how I fixed it, and what I screwed up along the way. Hopefully, others will learn from my adventure and screw-up.

How we got here:
- TV wouldn't stay powered on if the Antenna DTV was selected
- This led me to suspect the tuner unit, and here is where I screwed up. While taking the cover of the tuner module off to look around, I nicked a tiny tiny tiny trace. While looking under the microscope, it looked like all I'd done was scrape the solder mask, and didn't think more of it. Meanwhile, I did some reading and even reflowed the ICs in the tuner module.
- When I put it all back together, the original problem remained.
- I did a firmware update and the original problem was fixed!
- Then I noticed the TV wouldn't turn off, and created this thread.
- Replaced the MASTER and SLAVE eeproms. No good.
- Factory resets, Arduino to enter Factory Menu.. No good.
- Reprogrammed the SLAVE eeprom from a known good main board and I could power-off the TV... But I couldn't select Antenna DTV now.
- While trying all kinds of stuff in the standard menu and service menu, I realized it didn't matter which of the two eeprom codes I had loaded, I couldn't save any settings. Yes, the new eeprom allowed me to turn-off, but it didn't allow me to save other things. This made me take a closer look at the connections on the SLAVE eeprom and trace them out to where they went.
- Which brought me right back to the nicked trace from weeks ago. Testing continuity, I did in fact cut that trace, which goes from the large SoC to pin 2 of the SLAVE eeprom. Pin 2 is WC (Write Control). Ooops. Trace is so tiny, the 3mm piece of bare 30 gauge Kynar wire I used to bridge the cut, is about twice as wide as the trace.
- So yeah, the TV is fixed and I am watching it now.

Talk about a lesson learned! I want to stress to anyone reading this, how much fun and how much I learned throughout the journey. I also feel extremely happy for having stuck with it and thinking it through to the end. Of course, thank you ALL for your suggestions and expertise, for without you the entire circle may never have been made!

I consider this a total success. Thank you!

[nomoresonys]

Re: Samsung UN39EH5003FXZA won't stay powered off

Nice work, BRAVO to you for not giving up.