Insignia NS-50D550NA15 dead

[Prop1]

Hi guys, long time between TV issues. I got this Insignia that is dead. Checked for the 5v standby and it wasn't there, verified the fuse on the PS board was good. Am I correct to assume this is the PS board? I've also noted on ShopJimmy that the LED strips could be bad. Does one being bad rule out the other? Anyway of testing the LED strips without buying the PS board first?

Thanks for any help!

[budm]

Re: Insignia NS-50D550NA15 dead

Disconnect all other boards that are connected to the power board and then apply AC to the power supply board to see if the stby Voltage is present or not.
SJ sell LED tester.
http://www.shopjimmy.com/sid-gj2c-le...ght-tester.htm

[Prop1]

Re: Insignia NS-50D550NA15 dead

Will do. Thanks!

[Prop1]

Re: Insignia NS-50D550NA15 dead

Disconnected everything from board and applied AC.
STB =0v
12v =9.52v
16v =0v

Board and/or time to check LED strips? Thanks.

[budm]

Re: Insignia NS-50D550NA15 dead

Hmm, I need to see the pictures of the board.
I believe the STB pin on the power supply board is the same PS-ON pin, not standby power supply pin. So I need the pictures to verify what the STBY Voltage pins are.

[Prop1]

Re: Insignia NS-50D550NA15 dead

I'll upload pix tonight.

[Prop1]

Re: Insignia NS-50D550NA15 dead

Here's pictures of the whole back, PS board, and the connector pinout info. This board is a Hisense 170452.

[budm]

Re: Insignia NS-50D550NA15 dead

Hisense/Insignia 170452 Power Supply Unit
http://www.shopjimmy.com/hisense-170...pply-unit.htm#
Pictures provided by shopjimmy.
The standby power is 12V, not the typical 5V, so please verify that 12V to see what you really have when there is no other boards connected to the power supply board, and when all the boards are connected to the power supply board.

12V = 12V STBY SUPPLY
STB = PS-ON, to turn on the 16V and 12V supply (once main supply is on, the 12V from main supply is used to provide the 12V instead of 12V from stby supply).
SW = BL-ON
BTW, when you check the STB pin DCV, do you have all the connector in place?
I see you have 9V connector attached to the cables that go to the main board.

[Prop1]

Re: Insignia NS-50D550NA15 dead

I'll recheck voltages and get back with results. 9v connector was just for probing the cable connector.

[Prop1]

Re: Insignia NS-50D550NA15 dead

Here are the voltages with ps disconnected: 12v = 9.53v, stb = 0v, 16v = 0v, sw = 0v, pwm = 0v.

Voltages with ps connected (all connectors in place): 12v = 12.3v, stb = 3.35v, 16v = 0v, sw = 4.07v, pwm = 4.13v.

Thanks again for your help!

[budm]

Re: Insignia NS-50D550NA15 dead

OK, the switched 16V power supply is not working.
No power to TV and all the boards are still connected, then check the resistance between GND pin and the 16V pin to see what kind of resistance you have.

[Prop1]

Re: Insignia NS-50D550NA15 dead

I'm effectively charging a cap.

[Prop1]

Re: Insignia NS-50D550NA15 dead

I did some monkeying around and got the TV up and running. The picture has a gray background with 2 horizontal black bands at the 1/3 and 2/3 up the screen points. The 16v is running at 18.5v.

[budm]

Re: Insignia NS-50D550NA15 dead

So what did you do to get the 16V Switched supply to work?
So you do have images on the screen or just grey screen with lines? If it is just grey screen then the T-CON board is not working.

"I'm effectively charging a cap." What does that mean?

[Prop1]

Re: Insignia NS-50D550NA15 dead

So what did you do to get the 16V Switched supply to work?
So you do have images on the screen or just grey screen with lines? If it is just grey screen then the T-CON board is not working.

"I'm effectively charging a cap." What does that mean?

Forget that about the picture with the lines. I was half asleep when I made that non-discovery. The screen is totally black...and very reflective.

When I state that "I'm effectively charging a cap", the resistance starts at near zero and climbs over time to into the 10s of Kohms. But something did change after probing the ps board checking caps, diodes, and transistors. Here are the numbers now, TV off: 12v=12.37v, stb=3.35v, 16v=18.5v, sw=4.08v, pwm=4.13v and with the TV on (solid red indicator): 12v=9.4v, stb=.05v, 16v=.02v, sw=.02, pwm=.02

Main board issue? Blown LED strips?

[budm]

Re: Insignia NS-50D550NA15 dead

Forget that about the picture with the lines. I was half asleep when I made that non-discovery. The screen is totally black...and very reflective.

When I state that "I'm effectively charging a cap", the resistance starts at near zero and climbs over time to into the 10s of Kohms. But something did change after probing the ps board checking caps, diodes, and transistors. Here are the numbers now, TV off: 12v=12.37v, stb=3.35v, 16v=18.5v, sw=4.08v, pwm=4.13v and with the TV on (solid red indicator): 12v=9.4v, stb=.05v, 16v=.02v, sw=.02, pwm=.02

Main board issue? Blown LED strips?

TV OFF. TV ON reporting are backward?
12v=12.37v, stb=3.35v, 16v=18.5v, sw=4.08v, pwm=4.13v These readings should be for TV ON. iF If that the case then you do have all the correct Violtages and correct command Voltages. So YOU DO NOT have Backlights, right? If that is the case then we need to start check to see what DCV you have feeding the LED strings.

[Prop1]

Re: Insignia NS-50D550NA15 dead

TV OFF. TV ON reporting are backward?
12v=12.37v, stb=3.35v, 16v=18.5v, sw=4.08v, pwm=4.13v These readings should be for TV ON. iF If that the case then you do have all the correct Violtages and correct command Voltages. So YOU DO NOT have Backlights, right? If that is the case then we need to start check to see what DCV you have feeding the LED strings.

Yes, that is correct. Those voltages are when ON. No backlight is seen.

[budm]

Re: Insignia NS-50D550NA15 dead

You need to put black probe on the chassis, red probe on one of the two pins of the LED connector (LED connector in place) then turn the TV on and observe the DCV reading, wait a couple seconds to see if the Voltage drops down, then turn of the TV and then move the read probe to the other pin of the LED connector, turn the TV and observe the DCV reading again.

[Prop1]

Re: Insignia NS-50D550NA15 dead

Red lead = +240v {fluctuates +/- 10v}
Wht lead = -107v {solid}

Both to chassis gnd.

[budm]

Re: Insignia NS-50D550NA15 dead

240V, that sounds like you have no load (LED strings has open circuit). As you can see, the filter cap C955 for the Boost converter circuit is only rated at 250VDC (33uF), so 240V is pushing it.
You need one of this:
http://www.shopjimmy.com/sid-gj2c-le...ght-tester.htm