TV Repair help

#1

Morning all,

Our TV seems to have given up only six months after its warranty expired. (what a surprise!) hoping to use it as an excuse to understand more electronics and hopefully repair rather than replace it. I’m not sure which part is faulty. as it has a main board with the timing controller on it then a daughter board which connects to the actual display. The screen dust developed the fault whist we were watching it so no impact or anything.

Anyone with an idea which part is most likely at fault. I was looking into spares for the main board which are about £80 but want to check if this is the faulty part or not before I buy it.

Getting the whole tv to the space for diagnostics is a bit of a pain as I don’t drive but I can get the main board out if that the suspicious culprit.

TV is a Samsung 43 BU8000 2022
Ive tried all the Samsung suggested fixes as well as flexing the display and daughter board pcb, disconnecting and reconnecting the ribbon cable from the main board.

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@electrotechs

2 Likes
#2

Well, thinking aloud here…

Most of it is working or you wouldn’t get anything on the screen at all.

Do a careful visual inspection of the boards to see if there are any obviously burned out components or tracks.

The neat vertical stripe suggests that maybe some part of the signal to the display is messed up, which suggests the possibility that the ribbon cable connecting to the display either has a short or has one or more dead connectors or conductors.
If you have a multimeter/continuity tester and lots of patience, you could test each conductor in the ribbon cable for continuity and then test each pair of conductors to see if they’re shorted.

If none of that helps, get back to me and I’ll push the question out to the wider repair community.

1 Like
#3

I’ve just continuity tested the ribbon cable which seems fine and cleaned the contacts on it with a glass fibre brush with no luck. I cant see any components that look damaged. There are a pair of surface mount component pads on the daughter board that have solder but no component, they don’t look damaged though as the solder is smooth a slightly domed like a prepped pad.

You mention the signal might be the part being messed up; I did see one suggestion that the signal clock is different for each section. it suggested blocking the signal for a possibly the broken clock and the display may pick up one of the other clocks as a backup. not sure the best way to try this as I m not sure how to id which are the clock signals on the ribbon cable. guessing grounding them one at a time isn’t a great idea as some of them would be live power for the screen? or will the backlight be driven separately? My thinking is it would send the clock to ground and would need to pick up another signal?

#4

@vladisl0th - I’ve got the board ready to bring down. I’ve taken a picture of the pin our from the PSU board. Didn’t want to fiddle with the bare PSU too much but hopefully the legend on the board and the keyed cable should give us enough to work with? go the ribbon cable from the main board to the daughter board too.

Will be down tomorrow evening from about 6 if you are about.

#5

Would love to, but I’m not in London, maybe @sdsefwseghtqfg is willing to help?

#6

spoke to @sdsefwseghtqfg and apparently not the easiest to fix and we might not have the right tools. Have caved in a bought a new TV but would be nice to still fix this and sell it on. At least for a learning project if nothing else. I will see If I can get the whole unit to the space, possibly for an electronics night as I’m sure its easiest to diagnose as a full unit.