hisense f42k20e no backlight

[mattstolte]

I got this set the led lights red when I press power it goes blue but no backlights. all the voltages on the power supply are correct. the only thing im trying to determine if it is bad led strip or main? the bl/dim have 3.3 and 5v and then this lines going to the backlights the top + has 132.00v and the other 2nd + has none

[budm]

Re: hisense f42k20e no backlight

How about the pictures of the whole backside of the TV and the whole boards?
Turn the TV off then have the probe attached to the TOP + (PIN 1) keep an eye on the DCV meter when turn on the TV to see if the Voltage goes higher than 132VDC.
Then do the same again WITHOUT the LED connector in place, report the reading.
It looks like the two LED strings are connected in series to form one big string.

[mattstolte]

Re: hisense f42k20e no backlight

yes bud will get some tomorrow thanks. is there suppose to be no voltage on the bottom 2+ ?

[budm]

Re: hisense f42k20e no backlight

If the LED strings are connected in series, so if the first string is open then the other strings will not have any current flow through them to develop the Voltage drops on the other LED string.
Looking at you board, I would say it only has two LED strings and they are connected in series.
I expect the DCV on the connector to jump to > 200VDC when you first turn on the TV and then drops down to lower Voltage.

[mattstolte]

Re: hisense f42k20e no backlight

BUD the voltages do not change

[budm]

Re: hisense f42k20e no backlight

So it shows 132VDC when the power switch is activated and it did not jump higher that that at all?
BTW, if you have the LED connector hooked back up and you get no DCV at all on the 2+ pin, that will indicate that the +1 string has open circuit.

[mattstolte]

Re: hisense f42k20e no backlight

Yes none are line 2