Hello, everyone!

A friend of mine gave me a 70" Samsung TV that does not show image after pressing the power button... It's in a loop with the standby red light flashing two times while the TV tries to power on with a startup sound. You see, it occurs to me that I could try keep learning how to repair TVs out of this device, so I'll share some pics I took after taking the back cover out; I noticed that someone tried to repair it (or did it at some point) because I found a small power supply glued on the metal cover by the mainboard (3.3v IN and 13v OUT). The idea here is checking...

I am troubleshooting an AVT150 amplifier. The standby pin is at 0 V, so the amp remains muted.

I have the schematics attached.

Key observation:

• The standby pin is 0 V (muted condition).
• If I remove T104, the standby voltage is restored.
• With T104 removed, I have 4.7v on standby pin and TDA can see signal generated.

This suggests T104 (or its surrounding circuitry) is pulling the standby line low, but I am not yet certain whether this is due to a faulty transistor, a control signal upstream, or a protection condition being asserted.

Has anyone...

Hello, been a while since posting and always appreciate this forum and the help.

Picked up an LG OLED77C2PUA that does not turn on.

The standby light does come on when plugged in. Pressing the on/off button on TV (or LG remote) the red light turns off for 1 second and comes back on steady. I took off the back panel and tested the power supply. When pressing the power button, the 20V and 12V to Mainboard spike to 19.9 and 11.9 for a few seconds then slowly drop back off. Can tell the supply is coming on for 2-3 seconds. The 12V to TCON also spikes to 11.9 then drops back...

Have a Samsung UE43KU6400U that will not turn on, just continuous flashing red standby light.
Power button does nothing

Have unplugged the mainboard, and backlights illuminate.
Have tried removing panel ribbon cables one at a time, and that makes no change.

With mainboard unplugged, all voltages from powerboard seem ok, but with mainboard connected, they never quite reach full voltage, and drop and raise in a constant loop (in time with click noise from mainboard.

Using backlight tester, I get 63.6v on both sides, so seems like no bulbs...

The TV is a 2013 Samsung plasma, model # PN60F5300AFXZA.

Snagged it up in non-working condition a couple years ago. Previous owner said that sometimes he could get it to come on after repeated tries but other than that he couldn't get it to turn on.

Personally I haven't been able to get it to turn on at all. The standby light comes on solid when plugged in, but pressing the power button results in the standby light flashing once every 4 or so seconds. No "click" noises, no light from the panel at all. Just the flashing standby light.

No visible...