Hisense 58R6E 2 blink now power

[EazyBone]

So I've searched the threads and found this which is similar but not exactly the same.

https://www.badcaps.net/forum/showthread.php?p=1120104

Stby light is solid red, I hit power, flashes 2 times slowly and remains red. Doesn't flash anymore.

Getting voltages from 12v as 12v the 20v pins (or whatever) are constant 20 v the standby volt is 2.9v and they stay steady the whole time even when power button is pressed. The filters are about 390V and look fine.

I've disconnected every cable and tested and same result.

When I test the voltages for the backlight power and do positive/negative they do a weird cycling. Jumps to 200v and rapidly goes down to zero and repeats this cycle without hitting the power button. Does with cable connected and disconnected they cycle never changes. I tested with ground to chasis and the voltage to negative terminal of the power led is 220v constant where the other leg is 7v and drops to 0 and goes up and drops repeatedly. This cycled never changes.

Shouldn't the LED backlight power switch read a constant voltage?

The link shows a picture of exact power board and similar problem.

Attached is schematics also, I'm trying to learn how to read them so bear with me.

Thanks all! I'm having a lot of fun 😁😊😁😊

[R_J]

Re: Hisense 58R6E 2 blink now power

You have bad (open) led's in the panel, the led voltage would be around 160vdc if the led circuit was not open and was drawing current, the fact it jumps to 200v and shuts down is due to the over voltage protection cutting in.

[EazyBone]

Re: Hisense 58R6E 2 blink now power

You have bad (open) led's in the panel, the led voltage would be around 160vdc if the led circuit was not open and was drawing current, the fact it jumps to 200v and shuts down is due to the over voltage protection cutting in.

Yes but it does the dropping without leds connected. That's happening on the PSU regardless of the lights being connected. Not saying your wrong, but I thought the PSU would show a constant voltage or zero voltage if it wasn't plugged in and properly working.

Thanks for responding though, this is also where I was thinking

I did get my LED tester today so I'll write my report .

[lotas]

Re: Hisense 58R6E 2 blink now power

The constant voltage will be if the LEDs are all working, and if they are not working (break in the lines), then the protection in the backlight driver against overvoltage will turn off the power to the led backlight.

[R_J]

Re: Hisense 58R6E 2 blink now power

Yes but it does the dropping without leds connected. That's happening on the PSU regardless of the lights being connected. Not saying your wrong, but I thought the PSU would show a constant voltage or zero voltage if it wasn't plugged in and properly working.

Thanks for responding though, this is also where I was thinking

I did get my LED tester today so I'll write my report .

Having the led's disconnected is the same as having an open led circuit, an led tester is not likely to give a proper diagnosis as they only supply about 10ma of current, when the leds are driven by the power supply it is at about 300~400ma, the tester will likely be ok to check each individual led on the strips but can give false positive when checking a string of led's.

The N701 ic drives the led string return mosfet, basically the mosfet provides the return to ground for the led string and the current through the led string is monitored across R720,727,728,729,730 and fed back to N701 pin5, If there is no current, the ic shuts down the circuit.

[EazyBone]

Re: Hisense 58R6E 2 blink now power

Ahh super helpful. I have a decent tester hopefully but it did not turn on the lines actually. It tells me the ma when running the whole strip, I tested on another strip and it lit them up. But yes there is no light at all and the backlights are the problem. I guess we can consider this solved.

Free tv so I'm going to attempt to take apart and solder a new led in place and see what happens. Thanks all