Re: Samsung UN39EH5003FXZA won't stay powered off
LOL... I know I could have easily either disappeared or lied about the repair. Or even just said, I'd used the replacement mainboard and go bored... But, I would be more ashamed if I didn't admit my mistake! I'm sure many of you can relate.
When I saw the dent on the trace, which is right next to the tuner pins, the fact that I was getting video from that tuner, made me completely assume that trace was cool. It never crossed my mind, that the trace then went under the board and ran over to the eeprom. The actual damage...
Hannibal_Hector
Member
Last Activity: 06-16-2021, 11:30 AM
Joined: 03-02-2021
Location: Lake Hopatcong, NJ
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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...Leave a comment:
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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...Leave a comment:
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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....Last edited by Hannibal_Hector; 03-25-2021, 03:41 PM.Leave a comment:
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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: [url]https://github.com/ironman977/SamsungIRRemote[/url]
This popped up the factory stuff, and I did a Factory Reset. Unit shutdown and then auto-powered back up....Leave a comment:
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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...Leave a comment:
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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."
...Leave a comment:
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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...Leave a comment:
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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...Leave a comment:
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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.Leave a comment:
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Re: Samsung UN39EH5003FXZA won't stay powered off
And, I'm back... Received the new IC901, swapped it out, and lo-and-behold... The same fault! (I also did try the only reset I have access to, which says 'factory'.)
It is doing *exactly* the same thing with the new EEPROM.
I don't see any other non-volatile memory devices on the board, so I am left with some logic issue on the PSON line or a bad SoC. Given how literally everything else is working perfectly, I am not inclined to fault the SoC and strongly suspect some transistor or passive not allowing the...Leave a comment:
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Re: Samsung UN39EH5003FXZA won't stay powered off
Cool. Thank you for confirming this as normal behavior by the PSU. I hope replacing IC901 fixes it at this point, but who knows? I have had a lot of fun through all this either way.
@Diah, good theory, but it didn't work, LOL. The problem is that the PSU never gets power_on signal, so there is no way it could show anything. Also, while the red light is ON, it doesn't flicker when sending it IR, so I am not entirely sure the SoC is really 'alive' enough in this state. It might be stuck in a loop, waiting for the PSU signal...Leave a comment:
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Re: Samsung UN39EH5003FXZA won't stay powered off
I have the IC901 on order from Jimmy. Still, there is something nagging at me regarding the PSU in the face of @Diah's comment about it starting low.
On my original post, I note that the PSON line goes to 3.5V when he TV is on, and briefly drops to 0V when it goes OFF, and then jumps back to 3.5V.
However, if I disconnect the main board from the PSU, the LCD panel lights up and all of the voltages are present, including 3.3V on the PSON line. I am confused by this, since this doesn't appear to be how...Leave a comment:
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Re: Samsung UN39EH5003FXZA won't stay powered off
Ok, I have updates and some new knowledge.
Regarding the reset, the only one I can do is the first one from @vinceroger69's list, because I cannot put the TV into standby. However, the first one is only the Hotel mode. Interestingly, even if I put the TV into Hotel mode ON, it forgets that too. LOL
@Diah, providing some nice low-level activity... So, I read the 24512RP EEPROM with a CH341A, saved it just in case, and wiped it clean. This didn't work at all, and I wasn't able to power ON the TV and it never...Leave a comment:
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Re: Samsung UN39EH5003FXZA won't stay powered off
@Diah, the factory reset from the diagnostic menu didn't do it. Haven't tried the service menu, and I need to figure out how to get in there. Hopefully, it doesn't require the tv to be in standby!
@nomoresonys, that eeprom is the popular one, and I think it stores the configuration of the device, like the resolution, size, types of boards, etc. Yes? I am very curious about the other eeprom next to it, the so-8 size 24512RP. What does it store? I do not find mention of that one anywhere, with respect to this model. I...Leave a comment:
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Re: Samsung UN39EH5003FXZA won't stay powered off
Thank you all for your thoughts...
@dick_barton, "Are you able to do a firmware update."
Yes, I did the update and that solved the initial problem, which either created or revealed a new one.
@Diah, Now I need to figure out how to replace the flash chip. I haven't been able to find a source for a pre-programmed (I'm guessing that just means formatted appropriately.), so my alternative is to purchase a blank, pull the 'bad' one, read it, and write it to the new one. Of course,...Leave a comment:
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Samsung UN39EH5003FXZA won't stay powered off
Hello,
Purchased a broken Samsung UN39EH5003FXZA (Version CD01) to have fun fixing. When I first acquired it, I did not connect any video signals and only plugged it into the wall. The unit booted and showed the “no signal” window and I could navigate all menus and change sources. I unplugged it, connected my over-the-air antenna to the coax, powered it on, got the unit to scan the HDTV channels, and I 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... -
Re: New Members - please post your introductions here
Hi all,
Electronics hobbyist from New Jersey, USA. I enjoy the challenge of fixing stuff and the learning that is necessary to find the faults. I am comfortable working at the board level with smd components.
I was led here while searching information on a broken LCD set and will stick around to learn.Leave a comment:
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