Hisense f42k20e turns on, screen goes dark

[dick_barton]

Re: Hisense f42k20e turns on, screen goes dark

If you place your meter probes between the two legs of C810, what DC voltage do you have in standby and out of standby?

[x_orange90_x]

Re: Hisense f42k20e turns on, screen goes dark

I just realized the first picture of the back of the set is incorrect. Please ignore that one.

[x_orange90_x]

Re: Hisense f42k20e turns on, screen goes dark

Do you get the same reading if the connector to the LEDs is not connected?
It sounds like you have open circuit in the LED string.

Yes, I get the same readings without them even plugged in.

In the picture attached, the coil with the black bands on it makes a low pitch buzzing sounds when the tv is in standby, and stops when it's switched on. The large yellow block with the sticker on it makes a strange sound when the leds light up, then stops when they go off (even with them disconnected). The sounds it makes is a little reminiscent of a hard laptop drive if that makes any sense.

[dick_barton]

Re: Hisense f42k20e turns on, screen goes dark

Any pictures of your circuit boards would be useful.

[budm]

Re: Hisense f42k20e turns on, screen goes dark

Do you get the same reading if the connector to the LEDs is not connected?
It sounds like you have open circuit in the LED string.

[x_orange90_x]

I have a hisense f42k20e that powers on and the power light flashes between red and blue about 6-7x, then a couple more times and remains blue. The panel lights up bright white then fades to black. I can see images on the screen after it fades. When it lights up there is a quick buzzing noise that sounds like it's coming from the power supply, and when the screen goes black the buzzing stops.

I took the following voltages on the LED strips:

1+ -- spike to 280v, drops to 133v
2+ -- spike to 130v, drops to 0v

I'm not sure what these voltages are really telling me. They don't match what I have seen in the past with other tvs.