[Solved] Sharp Aquos LC-40LE824E Power Supply Issue: Replaced Electrolytic Capacitors, Still Fails

Welcome,

TV Sharp Aquos LC-40LE824E, for example, when increasing the brightness of the backlight or the colors to dynamic (which thus increases the brightness of the image) began to turn off and after a while it turned on again. It worked normally when set to ECO mode. After a few months, even dimming the image did not help, as it would not turn on. The TV is about 5 years old.
I understand that the TV power supply was not producing power. Therefore, in the power supply, I replaced all electrolytic capacitors with new ones, although none of them was swollen. It helped and everything returned to normal, but after 6 months the problem returned. Now it won't even turn on. It goes out a few seconds after it is turned on.
It seems to me that replacing the capacity may not bring the desired results. Everything looks ok on the board, nothing is overheated, I went through the diodes, they also look ok.
Does anyone have any idea what else I should pay attention to or replace.

ps
The power supply has the designation DPS-126CP-1 A, RUNTKA685WJQZ

"I walked the LEDs, they also look ok.
Does anyone have any idea what else I should pay attention to or replace. "

Traverse resistors, voltages, currents, capacities and inductances.

Soft check.

Thanks for the hints.
I will go through the suggested elements.

The soft will be a problem because the TV does not start anymore, but if it worked, what should I check, its version?

tporem wrote:

The soft will be a problem because the TV does not start anymore, but if it worked, what should I check, its version?

Ask what and how?

buli1 wrote:

Soft check.

buli1 wrote:

Soft check.

Thank you for the tip, but can you tell me what and how to do it? Is it just checking the version or maybe you mean entering the service menu and checking a specific parameter?

Soft is not a problem here, but the power supply (or matrix backlight).

You have SM for this RUNTKA685WJQZ Sharp / DPS-126CP power supply

Quote:

Power Supply RUNTKA685WJQZ Sharp / DPS-126CP

IC7801 NCP1608BDR2G
IC7901 ICE3BS03LJG
IC7601 ICE3BS03LJG
IC7702 DDA003A-SG240

Also helpful, for example, a topic from the forum Link

You have an idea about electronics, measurement and diagnostics, e.g. LED driver, you can fix it.
* if not, service
* MS may be helpful to others

TV started.
It turned out that one of the four optocouplers operating in the feedback loop between the primary and secondary parts of the power supply was broken. The more I thank my colleague for the power supply diagram.
At the anode (diode) of the optocoupler there was a voltage that triggered the diode, and yet there was no voltage drop between the collector and the emitter.
With a screwdriver I shorted the emitter with the collector of the suspect optocoupler and the TV started to work normally. Thus, I came to the conclusion that it is not working properly.
Unfortunately, getting the original optocoupler was quite difficult, so I replaced it with another one with similar parameters, ie LTV-817. I replaced all 4 optocouplers just in case. The total cost did not exceed PLN 20.00 Everything was fine and I have been enjoying a normally working TV for a long time.

For me, the replacement of optocouplers also helped
Thanks