Insignia NS-50d40SNA14not turning on

[henryvrensburg]

Hi guys

I have a Insignia as mentioned in the Title. If plugged into the outlet, the Standby light comes on, but the TV doesn't switch on. I tested the backlights with a backlight tester, seems to be working.

Voltages on the Power Supply as follows:

On Main Capacitor = 171V

ON Connector to Back Lights = 0V on any connector

On Connector to Mainboard (with Neg probe on chassis)

1 = 4.114V
2 = 0.0009V
3 = 0.945V
4 = 4.628V
5 = 0.0009V
6 = 5.096V
7 = 5.096V
8-16 = 0.000V

I'm thinking it is the Power Supply. You guys have any advise.

[captainKKK]

Re: Insignia NS-50d40SNA14not turning on

Since the 12v are not present, and the brown cap only has 171 volts, the secondary side of the PS is not turned on, either b/c of a PS fault or a non existent signal from the MB. Try to power on after unplugging CN3. If no 12v on any pinouts, then Check the PS fuses, bridge, mosfets and diodes. Can u provide CLEAR pic of PS?

[CapLeaker]

Re: Insignia NS-50d40SNA14not turning on

This PSU doesn't have a PFC, so 171V on the main filter cap is correct.

Either there is a short on the 12V rail on the main board, dragging the PSU down, or there is a problem with the 12V rail on the secondary side of the PSU. There are some big diodes... have a look at those.

recheck the backlights again.

[henryvrensburg]

Re: Insignia NS-50d40SNA14not turning on

- If I remove connector CN3, the TV does seem to try to turn on, because the Standby light goes out, but I still can't find 12V anywhere.
- If I power the Backlights with my Backlight Tester, there still is no picture.
- I tested all the diodes on the board, found the 5V on the D36 and D55, but can't find 12V at any point.
- I tested the backlights again, they do come on at 89,3V on both strips.
Bank 1 = 89,3V
Bank 2 = 89,3V

Thank you

[captainKKK]

Re: Insignia NS-50d40SNA14not turning on

good pics now. How about taking out your paint brush and knocking off the cobwebs everywhere, especially around BS1

[henryvrensburg]

Re: Insignia NS-50d40SNA14not turning on

Cobwebs taken care off, sir.

[CapLeaker]

Re: Insignia NS-50d40SNA14not turning on

check dm4 diode for a short.

[captainKKK]

Re: Insignia NS-50d40SNA14not turning on

Can we see the back of the PS, especially around CN2? Your power pins only have TWO 12vdc wires......on pins 10 and 13. There are no wires connected to 5, 9, 14. We need to see the back of this PS to trace pins 10 and 13. You did not say specifically you got 8, 11, 12, 15 and 16 showing grounded...are they to the chassis?

[henryvrensburg]

Re: Insignia NS-50d40SNA14not turning on

The Pins mentioned is grounded to chassis. Herewith photo of back of Power Supply

[R_J]

Re: Insignia NS-50d40SNA14not turning on

Does your voltage on CN2 pin3 change when you press the power button? You are likely not getting the PWR_ON signal to turn on the power supply

[henryvrensburg]

Re: Insignia NS-50d40SNA14not turning on

It stays at the same voltage, doesn't change if I try to switch it on

[neilc6]

Re: Insignia NS-50d40SNA14not turning on

I tested the backlights with a backlight tester, seems to be working.

LED failure is very common in these Insignias. Did you remove the panel to ensure all the LEDs are lit. If one or two are shorted, it may be hard to detect without visually confirming they are all lit. If probing through the LED connector, the voltage readings may not be the same if each wire pair isn't driving the same number of LEDs.

[R_J]

Re: Insignia NS-50d40SNA14not turning on

If the PWR_ON never chainges you will not get the power supply to turn on the 12 volts
If you want to rule out the power supply, disconnect CN2 from the main board, connect a 500-1000Ω resistor between 5.1v_STB (pin6 or 7) and pin 3, That should turn on the12 volts.l

[captainKKK]

Re: Insignia NS-50d40SNA14not turning on

After following R_J, report on voltage from PIN 10 and 13 of CN2, my bet that DM4 is bad, check please and report voltages / continuity on the 3 pins of DM4 (darn, that CapLeaker is smarter / faster than me and didn't even see the back of the board). Since CapLeaker can now SEE what he is looking for, I know he knows your answer. Pardon my tracing, but my resolution is not good and I took small guesses on the 2nd one.

[patrax]

Re: Insignia NS-50d40SNA14not turning on

Had this very set come thru about a month ago and fought it for three days till I finally removed the panel completely (Be very very gentle with these and use good quality suction handlers) and there it was staring at me surrounded by 50 some working diodes was the burnt black eyed sob. Replaced all 10 strips in less than 30 mins, BAM working set. Needless to say lesson learned remove the panel and check the LEDs guys very common failure in this brand.

[CapLeaker]

Re: Insignia NS-50d40SNA14not turning on

It stays at the same voltage, doesn't change if I try to switch it on

How did you turn on the back lights then?

[nomoresonys]

Re: Insignia NS-50d40SNA14not turning on

So whats the report on DM4?

[neilc6]

Re: Insignia NS-50d40SNA14not turning on

Bank 1 = 89,3V
Bank 2 = 89,3V

If these are your strips (pic found on ebay and some blog), you have a total of 8 x 4 = 32 LEDs. If they are wired into 2 banks of 16 and you are measuring 89V off each bank with an LED tester, then I would assume they are 6V LEDs and you have one short LED in each bank.

[patrax]

Re: Insignia NS-50d40SNA14not turning on

If these are your strips (pic found on ebay and some blog), you have a total of 8 x 4 = 32 LEDs. If they are wired into 2 banks of 16 and you are measuring 89V off each bank with an LED tester, then I would assume they are 6V LEDs and you have one short LED in each bank.

Exactly, you have a shorted strips which in effect is really hard to pinpoint.
These sets have some of the weakest leds Ive ever seen.
Every one of the strips I R&Red were yellow around the SMD on the strip and the unit I repaired had really low hours. I initially had thought I could replace just the shorted diodes until I realized just how low quality they actually were.
Play it safe and replace them all if want any reliability at all.

[budm]

Re: Insignia NS-50d40SNA14not turning on

https://www.shopjimmy.com/insignia-5...eprom-only.htm

Symptoms EEPROM replacement MAY fix:
- On screen display is stuck on logo screen
- TV won’t power on with remote or buttons (LED indicator remains same color)
- TV won’t turn on after being off for 30+ minutes
- TV shuts off by itself during channel scan or when switching inputs
- TV turns on and is stuck in color test pattern mode forever
- TV turns on but there is no backlight (LED indicator shows TV is on but there is no image)