Sceptre U550CV-UMR 4K LED, Bad Caps on Main Power Board?

[Dani_2024]

Hi and thanks in advance for any input you might provide!
I have a Sceptre U550CV-UMRD8POTV83BB 4K LED (this is a dumb tv) that I bought new in August 2021, so It's just completed 3 years.
Main power board model: TP.MS3683.PC821 T-Con board: N4TP546UHDPU2L_BO

Last Sunday I was watching a dvd and fell asleep for about half hour, when I awoke the tv screen was black and couldn't get the dvd menu to show, so I changed the input to antenna and had sound but no picture, turned it off. I then got online and found this great site! ....read many troubleshooting tips and this is where I'm at:
I do have sound and a picture using the flashlight test.
I tried the various power cycling methods including unplugging to de-energize capacitors and then restarting. The red power light does change to blue.
The tv powers on seemingly without trouble, I get the red logo flash, then the screen goes black.

Took it off the wall today and opened the back, this tv appears to only have a T-con and main power board.
I did the T-con ribbon off test for each side, no picture for either.
The main power board looks good at first glance BUT the 3 larger capacitors do NOT look entirely FLAT like the 2 smaller ones, the larger ones look (to me) like the tops are bulged. See pics.

I don't *think* its the backlights due to the usage, IF the tv was on 100% of the time that'd be 8760 hours per year, times 3 years= 26,280 hours...but I certainly didn't have/leave it on all the time. The backlight life is supposed to be about 80k hours...

My goal on looking inside was to general troubleshoot, do the T-con test and see if there were any obvious problems, I'm not up to attempting to solder anything or fixing backlights. Getting the thing down (and back on the wall) will be the best I can manage, I recently tore my ACL and supposed to have surgery within 2 weeks.

In my limited knowledge, I kinda think it's the capacitors, can you please take a look at the 2 pics and give me your opinion?
(I priced a main board replacement at about $50 and it looks easy enough to remove/replace, or am I mistaken on that?)
Again, thanks for your help.
Dani

[R_J]

Those 3 caps are definitely bad, try replacing them and see if that fixes the problem. The 3 caps are in the backlight boost circuit so are likely the problem.

[Diah]

Those 3 caps are definitely bad, try replacing them and see if that fixes the problem

yes they blown because LED BL one or more shorted / Open

[lotas]

Replace these three capacitors, they are responsible for the backlight voltage...

[R_J]

yes they blown because LED BL one or more shorted / Open

not likely

[EazyBone]

As they said it's those capacitors most likely. But don't get the idea that LEDs last 26,000 hours because that is very very far from true as I've replaced many many TVs with 1/10 of that with bad LEDs

[Diah]

not likely

if they realy blown... the currents will reduce to 80%, let say 90%.. if all LED as they are one channel will lit on very dim but they are not... just dark

[Dani_2024]

Those 3 caps are definitely bad, try replacing them and see if that fixes the problem. The 3 caps are in the backlight boost circuit so are likely the problem.

Thank you to R_J, Diah, Lotas and EasyBone for confirming my thinking.

Being I'm a crap solderer plus my current lack of attention due to pain, I was going to replace the whole board. #TP.MS3683.PC821 The problem now however, is finding one in stock. Does anyone have any ideas? I've checked tvpartstoday, torres tv parts, shop jimmy, and last resort fleabay.
Now I'm mad at myself because I closed the tv back up without writing down capacitor sizes/numbers. Duh.

Anyhow, Thanks for your help!

[EazyBone]

Got to open it back up or see. if another picture on the net has a close up maybe it will show you. Caps are very easy to solder, don't need to be super careful like smaller components, just make sure you use flux!

[lotas]

And if you are planning to change the motherboard itself, then there may be a problem with the firmware of your model and the one you purchase, the remote control will not fit, the buttons on the TV are mixed up, the image may be upside down, since the firmware will not match your panel...

[Dani_2024]

Ok, I'm going to attempt to replace the caps...if I ever get them. I've ordered the Caps online from Mouser and I'll say that they have the WORST customer service, and get real nasty when you point out they've made the mistake that has made you call them in the first place. Don't bother trying to communicate via online chat, because those reps are offshore and clueless. You have to call. Their website claims they ship same day if you order before the time noted by their live countdown cutoff clock, but my order didn't ship same day, even though I ordered it about 1pm eastern time and paid for expedited shipping. Sure they created a shipping label that day, but UPS never got the package until the next business day, which obviously slows the transport. Don't order from them if you need parts within a few days, (even though they claim to have thousands in stock) and don't pay for expedited shipping, it's a scam.

[EazyBone]

What are the cap ratings? What v/uf?

[Dani_2024]

the bad caps:
qty 1 22uf 250v 12mm wide, 12.5 mm tall part# UCY2E220MPD
qty 2 39uf 160v 12mm wide, 12.5 mm tall part# UCY2C390MPD
these are for board numbers 104/107, 105/108 and 801
the ones I ordered were 16mm tall, I don't think larger (taller) would fit.

[EazyBone]

They will probably fit. Just looked them on Amazon, 1 day delivery for the first one anyway. Alright keep us updated

[Dani_2024]

Update: I've changed out the 3 bad caps and managed to get the tv back together and tested, success! I had it on for a few hours last night and all appears to be good.

Issues with the fix: At least one of the caps had been leaking down the back of the pcb and cleaning it took a long time. (Used cotton swabs and isopropyl alcohol) I was looking for better rated caps for longer life, but the ones I found that matched the uf and exceeded the voltage looked to be too big to fit under the tv's back cover. (I bought extras since they were cheap and the shipping was high.) There were a few spots on the board that looked slightly discolored like it may have been hot at some point, which I wasn't too surprised to see. The tv is mounted on the wall and hadn't been getting much airflow. While I had the plastic pcb cover still off, I used a dremel to cut a few of the narrow vent slots off/out for more ventilation and heat release. I'm going to find a small fan to mount behind the tv as an extra precaution and I bought a new surge protector, one with the cable in/out connections.

I've also reviewed my display settings and further lowered the backlight power to about 40, reduced the contrast, sharpness etc.

Thank you so much to everyone who gave advice and helped me complete this repair,I really appreciate you!!
Dani