Samsung UN60EH6000FXZA occasionally won’t turn on

[DXseekerMO]

Hello everyone, this time I'm working on a Samsung UN60EH6000FXZA that occasionally will not turn on. If the TV is left unplugged for some time it takes quite a while (days sometimes) for the problem to show up. When it does the power button on the remote or jog switch is pressed, the stand-by light will start flashing but the opening jingle doesn't play, the backlights do not turn on and the TV will go back in to stand-by mode. Sometimes with several tries the TV will eventually power on. The previous owner said if they plug-and-unplug it several times that the TV was more likely to power on. My first impression by symptoms was bad electrolytic caps on the PSU or a bad EEPROM.

I have yet to find any “Samwha” caps on the power supply, it looks like it may have been re-capped. As for the outward appearance of the electrolytic caps they all look good. Right now the TV is working. This is why I've not posted any voltages.

Would anyone have any troubleshooting advice for this issue? Thank you everyone!

[budm]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

Did you inspect the female connector at both ends of the cable that goes between main board and the power supply board?
You should also check the Voltages on the connector to see what you have or not have when it acts up.

[DXseekerMO]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

Did you inspect the female connector at both ends of the cable that goes between main board and the power supply board?
You should also check the Voltages on the connector to see what you have or not have when it acts up.

I went ahead and inspected them both. Were you referring to the one slightly misaligned on the main board?

I may only get one or two shots at getting voltages while it acts up because it may go back to working for a while. That said which line do you think I should check first, PS_on?

EDIT/ADD: Another thing....does anyone feel PS_on (actually labeled POWER_ON) voltage of 3.6 with the TV running seems a little on the high side?

[CapLeaker]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

EDIT/ADD: Another thing....does anyone feel PS_on (actually labeled POWER_ON) voltage of 3.6 with the TV running seems a little on the high side?

No.

[budm]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

I went ahead and inspected them both. Were you referring to the one slightly misaligned on the main board?

I may only get one or two shots at getting voltages while it acts up because it may go back to working for a while. That said which line do you think I should check first, PS_on?

EDIT/ADD: Another thing....does anyone feel PS_on (actually labeled POWER_ON) voltage of 3.6 with the TV running seems a little on the high side?

I am looking for over heated of the connector due to bad contact resistance.
PS-ON: > 2V = ON, <1V = OFF.
Use this as a guide as to what the typical control signals should be: Samsung_UN50EH5000FXZA_fast_track_guide

[CapLeaker]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

I guess you have to measure the voltages when the TV doesn't want to start. I agree with budm's theory or a bad EEPROM. When the TV doesn't start freeze the EEPROM with a can of air upside down, the try to start it.

[DXseekerMO]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

I am looking for over heated of the connector due to bad contact resistance.
PS-ON: > 2V = ON, <1V = OFF.
Use this as a guide as to what the typical control signals should be: Samsung_UN50EH5000FXZA_fast_track_guide

Thank you for posting this budm, also there are no signs of overheated connectors on either board.

I guess you have to measure the voltages when the TV doesn't want to start. I agree with budm's theory or a bad EEPROM. When the TV doesn't start freeze the EEPROM with a can of air upside down, the try to start it.

I'll have to go get some tomorrow and have it handy.

[nomoresonys]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

Maybe check the esr on your startup caps, could try hitting those and other areas with a hairdryer as soon as it acts up, see if it comes right back on.

[DXseekerMO]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

I've resorted to using this as my primary TV to try and get it to act up. So far it has turned on every time! lol how do I get so lucky?

[DXseekerMO]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

So still yet....the TV hasn't acted up. It's in my living room, my primary TV for now and I've turned it on and off several times without issue.

Here's a pic of the main board, notably the connector for the PSU which isn't fully seated. I believe it may have been this way when I got it. Does anyone think it's possible this may have been causing the problem?

[DXseekerMO]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

FINALLY....a glitch! I removed the antenna cable to put it in a different TV for testing. This way I could watch the other TV and just keep turning this one on and off. I turned it on and the background screen was solid red. I tuned a channel and there was LOTS of red speckles on the screen. Messed with the LVDS cable at the main board and the red went away.

Looks like I'm cleaning the LVDS cable and connections!

[budm]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

But in post #3 you said you inspect both ends of the connectors so you had to remove it from the board to inspect and see if it has any sign of overheated, right?
BTW, what we are looking for on the connector is something like this:

[DXseekerMO]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

But in post #3 you said you inspect both ends of the connectors so you had to remove it from the board to inspect and see if it has any sign of overheated, right?
BTW, what we are looking for on the connector is something like this:

I took a look at post #3 and realized I forgot to tell you that I took the photos before touching anything.

There are no signs of overheating on the connector or plug, definitely nothing like the picture. I see how that could cause a real problem!

UPDATE:

I removed the main board, cleaned both the LVDS connection, PSU connections and checked the grounds. Next I cleaned the connections on the LVDS cable, both sides. I did not clean the LVDS connector on the T-CON, but I will soon.

PREVIOUS OBSERVATION:

I started to notice that when I changed channels the audio came up, but it took around 3/4 to 1second for the OSD to come up.

After cleaning there is a VERY NOTICEABLE DIFFERENCE in picture quality. The OSD is much more crisp and clear, even the refresh rate looks better (less jerking in action scenes) as do the colors. Now when I change the channel the audio and video arrive simultaneously! Sometimes the video displays before the audio.

The difference in video quality is simply night and day. I am astounded by the dramatic change!

This makes me wonder about the integrity of the connection at the 12v line on the LVDS and whether or not low or inconsistent voltage was the problem?

[budm]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

Also make sure all the boards mounting screws are tight since the boards are grounded to the chassis via board mounting screws.

[DXseekerMO]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

Done, save for the T-CON....I'll get it when I clean the rest of the FFC's up.

The biggest difference I see is with lower definition streams, 480i/720p (as I am on broadcast TV) and the big improvement in color. It really stands out.

The more I see the more I'm starting to believe my diagnosis of bad connections causing problems when powering on. These thoughts later expanded to wonder how many bad LVDS and FFC connections have led to display panel failure by way of stress from being underpowered?

[DXseekerMO]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

So I cleaned up the T-CON LVDS connector, FFC connectors, FFC cable and the FFC connectors on the source driver boards. They were in pretty good shape but I was already there and committed to their cleaning. The T-CON mounting screws were tight.

When I flip channels the OSD and sound appear almost immediately now, slightly quicker than before these remaining items were cleaned.

The TV is turning on and off normally now, and if it continues to do so for the next couple days I will probably approve the repair and it will be ready to go.

[nomoresonys]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

Nice troubleshooting, those connections mustve been pretty dirty.

[DXseekerMO]

Re: Samsung UN60EH6000FXZA occasionally won't turn on

Visually they didn't look terrible, and diagnostic wise I would have never suspected an LVDS problem had the screen not gotten wonky yesterday. I guess I'll have to chalk this one up to good fortune and Badcaps for the knowledge I've gained! As soon as it happened I knew it was an LVDS problem from experience gained here.