SAMSUNG UN55JU6500F sound cuts out if too loud

[triplefour]

everything seems fine with this tv except when i turn the volume up past a certain point or leave the tv volume the same but turn up the source volume, past a certain loudness coming from the tv speakers, the speakers start to cut out. has anyone else seen this kind of problem before?

by the way, sound is fine if i switch to external

i measured the voltage at the connector that goes to the speakers. 4 wires, + and - for each speaker. voltage on the + wires is the same for both speakers, and is 1.5v on real quiet volume, moving up to about 2.0v when i turn it up, but once it gets over 1.9 it cuts out and i see the voltage (on both speakers) spike to 2.5 before dropping back down to ~1.9 when the sound cuts back in, and then back up to 2.5..over and over until i turn it down to where the voltage always stays under 2.0...it plays fine like this...but if suddenly something loud should happen, the voltage will go over 2.0 and sound will cut.

what could it be? i have never seen this one before

[triplefour]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

well jeez. i tested it pretty much all day yesterday, and most of today, and then i turned it off to go get dinner, came back and tried to turn it on but now i just get a blank screen with no backlight. power on/off and remote is ok, sound is ok... but no backlight! if i unplug the tcon i get backlight again. if i unplug either side of the panel from the tcon i get backlight again. if i have both sides of the panel's ribbon cables connected to the tcon at the same time, i get no backlight. also the blue LED on the tcon only comes on for a half second then goes away. with either side disconnected, the blue led stays on. with either side disconnected, i get a completely blank, black, backlight screen. i do not see any difference between the left side and the right side of the screen, as usual when disconnecting one side of the panel...

what the HELL is going on here? TCON's are cheap and im about to spring for one. this is a really nice 4k tv that up until a second ago was working flawlessly except for the fairly minor sound issue!

[CapLeaker]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

I guess at this point, I'd check and see if there is a main and tcon board combo to be had and change both, since the TV is fairly new. At this point there are multiple problems on multiple boards...

The sound issue is probably something with the sound IC on the main board. If it cuts out, freeze it with a can of air upside down and see what happens, but this is redundant now.

[triplefour]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

i keep wondering about this freezing trick..how does it not short out components when you turn on the tv and the ice melts, it gets water all over the board?

i ordered the tcon only for 18$ the motherboards go for almost 100...

[CapLeaker]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

it doesn't. Never shorted out on me. It's not like a high voltage situation here.

[triplefour]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

ok well hopefully i get picture back on this tv with the new TCON, and then ill try the freezing trick on the sound IC. so strange how it was working fine all day and then poof

[WildPuppy]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

OFFTOPIC:

i keep wondering about this freezing trick..how does it not short out components when you turn on the tv and the ice melts, it gets water all over the board?

Actually it is not water that you see there, it is liquefied compressed air, which is pre-dried (has a very low water vapor content) when it is put in the can.
When the liquid is decompressed as it is leaving the can, it turns back to gas state consuming energy. This process is what absorbs heat and cools the parts to very low temperatures.
As air is not a very good conductor, there are no shorts.

[triplefour]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

thank you for this mind-put-at-easing explanation

[Th3_uN1Qu3]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

That is a very good explanation indeed. I have been worried about this too at some point - but i've freeze sprayed enough sensitive components already, and never damaged anything. Never bothered to seek a technical explanation though.

[triplefour]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

got the replacement tcon today, and now im getting this
looks like bad panel stuff but i hope i could be wrong, or its fixable somehow...
i still dont understand..it was working fine, everything great except the sound issue, i turned it off for maybe an hour, turned it back on and got no backlights. this was with the original tcon, which i tested one last time before swapping it, which now flickers and fades erratically the blue light on it even when the tcon is not connected to the panel at all. and when it dims too much it resets the tv. if the tcon is disconnected from mainboard, backlights stay on and tv doesnt reset.
switching to the replacement TCON i get what you see in the pictures. the left side displays something, but has a few vertical lines, and the text seems stretched taller, and cut off/spliced weird.
the right side displays only black except for a 4 inch vertical bar that is doing crazy shit, moving from top to bottom real fast in a loop.
can a bad TCON take out a panel, or vice versa?
am i screwed here or what?

[budwich]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

can a bad TCON take out a panel, or vice versa? probably not directly but maybe a bad audio section can impact powering / dc levels / grounding in other circuits that might have taken out a capacitor or two in the bottom edge board. :-(

[triplefour]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

so are you saying a bad mainboard can take out a panel? but it has to go thru the TCON first...wouldnt it just take out the TCON?
what can i do, if anything to try to salvage this game of whack a mole?
can i actually repair the edge board? (this is the thin board that connects to the panel itself, yes?)

[nomoresonys]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

Bad panel can take out tcon. https://www.youtube.com/watch?v=yTnkOfwBGGE

[nomoresonys]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

If all your lines are vertical, you may have gotten a bad tcon replacement.

[budwich]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

so are you saying a bad mainboard can take out a panel? but it has to go thru the TCON first...wouldnt it just take out the TCON?
what can i do, if anything to try to salvage this game of whack a mole?
can i actually repair the edge board? (this is the thin board that connects to the panel itself, yes?)

my response was just a "suggestion" of possibilities BUT it is also possible that the main board (that has the sound processing on it along with other things like maybe switched voltage control going to the tcon) is impacted.

[triplefour]

Re: SAMSUNG UN55JU6500F sound cuts out if too loud

ok well i would like to believe my panel is still good but what can i test to narrow it down for sure?