Samsung TV Continuously Turns on and off (power cycle)
I have a 50” Samsung TV model number UN50TU8000FXZA, I dont know much history about the TV. There is a date of 2019 on the power supply board. I have done the following troubleshooting so far:
When plugging in the TV, the Samsung logo comes on the screen, and within 1-2 seconds the logo becomes partially garbled, and additional 1-2 seconds the tv turns off and then turns back on, starting the cycle again. When plugging in the tv, i can see the leds on the back go through 3 stages of brightness and on the last (when they are the brightest) the logo comes on. I reseated all internal cables with no change in symptoms.
Steps done so far:
- I checked all capacitors on the power supply board, no bulging tops.
- I left the TV plugged in for about 5 minutes and the cpu on the main board registered 125 degrees F. Seems hot for a resetting/non functioning cpu, but i dont know what to expect.
- Disconnected the cable to the main board. Plugged in the TV, the LEDs come on and I measure the following voltages in order at the LED connector on the power supply: 209V, 171V, 171V, 96V.
- On the power supply board, the voltages for the main board connection are as follows: 1-G, 2-G, 3-13V, 4-3.3V, 5-13V, 6-3.3V, 7-13V, 8-0-1.4V, 9-13V, 10-0V, 11-G, 12-0-1.6V. Pins 8 and 12 fluctuate between 0 and 1.4/1.6 volts, it spends about 3 seconds at 0 volts, then changes to 1.4/6 and drops back to 0.
Does anybody know if these voltages are in spec? the pins at 13V are correct, there is a label on the board, but the remining pins are descriptions, not voltages. I’m wondering if pin 6 should be 5v? Anybody have any other steps I can try? I can’t really find much in the way of schematics online, so i’m kind of stuck as to where to go next. I really hate to throw money at parts, i’d rather have make an educated guess. My initial thought from what i can tell is the power supply seems ok, it is puzzling i dont see 5V anywhere, which is what drives a lot of electronic boards. I suspect the main board but hoping there is a way to further diagnose.
Questa è una buona domanda?