TCL 75S421 has sound but no backlight not even a flash

[triplefour]

Holidays indeed. I still haven't been able to find the time to replace that capacitor. I did have a look around my scrap parts yesterday and may have found some donor candidates. Ohms reading on multimeter is not the best test for capacitors. Need a component analyzer. Which I do have. Will post more soon.

[triplefour]

Here's the bad cap. It does read open with ohm meter on highest setting and reads unknown or damaged component on the component analyzer. Usually in ohms with a working cap you will see some low resistance that climbs to infinate once the cap is charged.
I can't figure out what manufacturer makes this part. I don't recognize the symbol and can't find it in the list (see attached )
how can I tell what the capacitance should be? I would like to find the datasheet but without the manufacturer I would go off another manufacturers datasheet which may not be the same?
I Think the 333 means 33 nanofarads...from looking at other manufacturers markings.
I get putting in a 2kv replacement for future proofing the tv but what of the capacitance? Do I have to get it exact ?

[nomoresonys]

Yes .033 uf, 33 nanofarads, see if you have something close and give it a try.

[ChattFix]

Here's the bad cap. It does read open with ohm meter on highest setting and reads unknown or damaged component on the component analyzer. Usually in ohms with a working cap you will see some low resistance that climbs to infinate once the cap is charged.
I can't figure out what manufacturer makes this part. I don't recognize the symbol and can't find it in the list (see attached )
how can I tell what the capacitance should be? I would like to find the datasheet but without the manufacturer I would go off another manufacturers datasheet which may not be the same?
I Think the 333 means 33 nanofarads...from looking at other manufacturers markings.
I get putting in a 2kv replacement for future proofing the tv but what of the capacitance? Do I have to get it exact ?

I have the same issue, what did you end up replacing it with? I have a bunch of other boards I might be able to pull from but wanted to check with you.

[Cornito]

Hello,

I have the same issue on a 65c715 TCL, I've replaced the c614 cap and tv returned to life.
But 24h after same issue.

Is there anyone who knows the reference or part number of the 65c715 TCL.
I'd like to avoid double dismantling.

Regards

[Cornito]

Part number of the led strips, I missed to finish my sentense

[mecha1166]

Hi! I have one of these tvs here. Problem is it plays about 5 to 20 mintutes, picture is fine. Then picture goes blank but backlights stay on. I can shut off tv with power button. Unplug tv 15 minutes and reset, it will come back on another 5-20 minutes and lose video again but backlights stay on. I have lready tried main & tcon. Any ideas? Panel itself or power supply? The backlights should be good, as they stay on.

[mecha1166]

I found a scrap power supply that came from a set with no backlights. Cap looked normal, but replaced it anyway. Tried it in this set, backlights but still cuts off. So not helping on my tv, but wanted to let everyone know the backlight problem can be fixed with the capacitor. The capacitor can look good but still be bad!

[EazyBone]

Got me a 75s425 and had picture with no backlight. Tested backlights and all working fine. Tested voltages at backlight and one line was .9 and other .18. remembered this thread and pulled it up. Replaced the cap mentioned above with a higher uf from another board. All working correct again. Extremely easy fix. Thought I'd add to this. Thx to whoever figured it out.

[Cornito]

Hello easybone, take time to test it during days.
I've this on mine, worked perfectly some days and then I had the issue back, just unplugged and plugged back the connectors solved the issue. And few hours, or restart later, the issue came back.
No way to fix it on my side, broke the panel trying to remove it

[EazyBone]

Hello easybone, take time to test it during days.
I've this on mine, worked perfectly some days and then I had the issue back, just unplugged and plugged back the connectors solved the issue. And few hours, or restart later, the issue came back.
No way to fix it on my side, broke the panel trying to remove it

Interesting. The voltages seem correct and the LEDs. I also upgraded the capacitor to a higher one. Time will tell