HISENSE F42K20E LED Tv - No backlight

[budm]

Re: HISENSE F42K20E LED Tv - No backlight

What DCV do you have on C848 (Input Voltage to boost converter)?
The Cathode of the LED string should be connected to the Drain pin of the PWM Controlled MOSFET U703, the Source will be connected to the current sensing resistor, and another end of the resistor is connected to GND return. The Vdrops on the current sensing resistor is used for feedback to maintain constant current.
If you look up the spec sheet of IC U701 LED driver IC it may have example circuits on how it is used.
BTW, I think the MOSFET designators are 'V'xxx, and ICs are 'U'xxx.

[caphair]

Re: HISENSE F42K20E LED Tv - No backlight

132v on c848 and 260v to led pin 1+ which is over what the board has labeled at 245v

Is this due to the random inductor I soldered in for L702?

Backlights work still but L702 gets pretty hot to the touch

[budm]

Re: HISENSE F42K20E LED Tv - No backlight

132v on c848 and 260v to led pin 1+ which is over what the board has labeled at 245v

Is this due to the random inductor I soldered in for L702?

Backlights work still but L702 gets pretty hot to the touch

OK, I thought you are still getting only 132V with the sub inductor you have installed.
Ot sounds like the sub is not the right one to use.
Can you look at the old inductor to see if the open circuit can be fixed.

[caphair]

Re: HISENSE F42K20E LED Tv - No backlight

I can't see the windings they're incased. Did you see the picture of it I provided in an earlier post?

[budm]

Re: HISENSE F42K20E LED Tv - No backlight

I can't see the windings they're incased. Did you see the picture of it I provided in an earlier post?

I do not see the side view.

[caphair]

Re: HISENSE F42K20E LED Tv - No backlight

Here's a side view shot

[budm]

Re: HISENSE F42K20E LED Tv - No backlight

FERRITE pot, i have no idea where to get the replacement, the print on top looks like LEI-302B.

[caphair]

Re: HISENSE F42K20E LED Tv - No backlight

Could I use anything else that'd be similar?

[budm]

Re: HISENSE F42K20E LED Tv - No backlight

You need to get the right inductance, current rating, dc resistance.

[caphair]

Re: HISENSE F42K20E LED Tv - No backlight

Yes I wish I knew the specs of it.

I was playing with color options/brightness etc and with the random inductor I have in currently, there was no change to brightness or anything. Most likely bc the LEDs are being overpowered.

Would that be a result of a lower inductance or higher? As the voltage to the LEDs is 15v more than its supposed to be

[budm]

Re: HISENSE F42K20E LED Tv - No backlight

I have no idea. You may want to look up the spec sheet of the LED driver UC701 to see if they have any explanation on how it works.