Re: No backlight on Insignia NS-50DR710NA17, need help with voltages
Yes that is possible, the ShopJimmy listing might not be the right one.
Alright, I'm going to have to keep this aside for a couple of days, I will let you know if there's something new to share. Thanks again!
jayanth_rk
Member
Last Activity: 01-30-2020, 10:04 PM
Joined: 01-29-2020
Location: Irvine, California
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Re: No backlight on Insignia NS-50DR710NA17, need help with voltages
Great explanation, I understand that now.
I just checked -VLED when connector is disconnected. It falls to zero cleanly, there is no residual voltage coming from the MOSFET. I will try to get a resistor and do what you described.
Strangely, the -VLEDs now read about 4.4V when the connector is in place, instead of the 1.5V I saw earlier. Not sure why that change would be. The potential difference would still be over the total Vf though.Last edited by jayanth_rk; 01-30-2020, 02:19 AM.Leave a comment:
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Re: No backlight on Insignia NS-50DR710NA17, need help with voltages
Sorry, I don't quite understand that.
To my understanding, +VLED (53.8V) is positive terminal for both of the LED strings, and -VLED1 and -VLED2 are the negative terminals. -VLED is output by the power supply board to be about 1.5V, which creates roughly 52 volts of potential difference between the ends of the LED strings.
What happens when -VLED is connected to ground via a resistor?Last edited by jayanth_rk; 01-30-2020, 01:43 AM.Leave a comment:
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Re: No backlight on Insignia NS-50DR710NA17, need help with voltages
Oh I was referring to your point, "turn on the TV while keeping an eye on the meter to see if the Voltage jumps higher than 60V or not". That doesn't happen.
Unfortunately I don't have any resistors with me at the moment. What did you have in mind?Leave a comment:
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Re: No backlight on Insignia NS-50DR710NA17, need help with voltages
This is definitely just a one-time project. Yeah I really wanted to avoid opening up the panel. Thanks for all the help, I'll probably end up opening it and verifying the LEDs.
What does the fact that there are no initial voltage spikes indicate? Could it mean that LEDs are fine after all?Last edited by jayanth_rk; 01-30-2020, 12:30 AM.Leave a comment:
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Re: No backlight on Insignia NS-50DR710NA17, need help with voltages
Hmm yes, that would mean the voltage is right. There are no backlights at all, I just checked that again.
I think the only thing to do now is buy a pair of suction cups and have a look at the LEDs.Leave a comment:
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Re: No backlight on Insignia NS-50DR710NA17, need help with voltages
1) Okay, I see the blank areas on the board.
2) No, there is no voltage spike. +VLED goes up to ~36 V when the power cord is plugged in (But TV is turned off), and ~53.8V when I press the power button. Whether or not the connector is in place makes no difference to the voltage.
3) Attached. Is that the sticker you mean? The number is TPT500U1-QVN03.U...Leave a comment:
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Re: No backlight on Insignia NS-50DR710NA17, need help with voltages
Thanks for the detailed response.
Voltages on CN9103 (Power supply board to main logic board):
Pin 1, DIM: 2.836 V
Pin 2, BL/OF: 3.264 V
Pin 3, PS_ON: 3.317 V
Pin 4, NC: 0 V
Pin 5, GND: 0 V
Pin 6, GND: 0 V
Pin 7, GND: 0 V
Pin 8, GND: 0 V
Pin 9, +12VA/+16VA: 15.93 V
Pin 10, +12VA/+16VA: 15.94 V
Pin 11, +12V/+16V: 15.92 V
Pin 12, +12V/+16V: 15.92 V
Pin 13, +12V/+16V: 15.92 V
Pin 14, +12V/+16V: 15.92 V
Pin 15, +3.5V/+5V:...Last edited by jayanth_rk; 01-29-2020, 02:44 AM.Leave a comment:
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Re: No backlight on Insignia NS-50DR710NA17, need help with voltages
Attached a picture of the whole back of the TV. The connector in the earlier picture is at the top left of the board, and its thick black cable goes behind the back plate....Leave a comment:
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No backlight on Insignia NS-50DR710NA17, need help with voltages
I have an Insignia TV (NS-50DR710NA17) with the power supply board PLTVFY411XAF7. TV works fine, but the backlight is not functioning at all.
The output connector to the LEDs from the power module is seen in the attached picture.
Between the chassis and +VLED, I'm only seeing about +36.5V DC. The -VLEDs show about 34-35V DC when the connector is plugged in. This is definitely too low, right? I could take apart the TV completely to figure out how many LEDs there are, and what the voltage should actually be, but I'd rather avoid that.
Is there anything else on... -
Re: New Members - please post your introductions here
Hello, I'm a Computer Engineering student from Irvine, California!Leave a comment:
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