Vizio M370NV Powers on for 2 seconds then shuts down

[MisterD]

Has a normal Amber Vizio Logo, goes to White Logo when powered on, screen lights up and displays that Vizio logo on screen, stays on 2 to 3 seconds then powers down by itself. this happens each time it is powered on. I haven't disassembled it yet. I'm thinking possible LED strip open or shorted. any thoughts? Thanks.

[nomoresonys]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

With tv unplugged from outlet, unplug cable from powerboard to mainboard, plug tv back into outlet, see if backlights come on and stay on.

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

Thanks, I will get to that as soon as possible, other things going on right now. I just got this Vizio from a garage sale and haven't had a chance to disassemble it yet. hopefully Tuesday of this week.

[CapLeaker]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

probably bad LED(s) in the backlight.

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

With tv unplugged from outlet, unplug cable from powerboard to mainboard, plug tv back into outlet, see if backlights come on and stay on.

.........I Unplugged Cable from Powerboard to Mainboard and just as I thought no power to Mainboard therefore TV would not power on at all.

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

This camera is not very high quality but here are some pictures

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

I have an isolation transformer, can this be used on this TV at a lower voltage setting? maybe set it at 90 or 100 volts or would that not be advisable on these flat screen tv's? we used this method on the older CRT TV's when they had a shutdown problem and could keep them powered on at a lower voltage for troubleshooting purposes.

[R_J]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

Your isolation transformer/with switched output, won't help, this power supply is universal input 100~240vac input and it will have no real effect on the power supply voltages.
You should be able to check the power supply/backlights by:
disconnect the cable between main and power supply boards
using a few 470Ω~1kΩ resistor
Connect one between 5.1VSB and REMOTE_ON/OFF (this should turn on the power supply)
Connect one between 5.1VSB and BL_ON/OFF (this should turn on the backlight but may need dim signal)
Connect one between 5.1VSB and DIM_PWM_SIGNAL ( this should turn on the backlight)

[nomoresonys]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

.........I Unplugged Cable from Powerboard to Mainboard and just as I thought no power to Mainboard therefore TV would not power on at all.

The tv isn't meant to turn on and work, it's a test for certain psu and backlights, comprende?

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

I will have to see if I have the resistors if not I can get them from a local TV Shop, too bad Radio Shack closed down. CN201 doesn't have anything plugged into it.

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

The tv isn't meant to turn on and work, it's a test for psu and backlights, comprende?

Yes, I understand post #8 using the resistors. Thanks

[R_J]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

Check the value of R341 and R327, if their value is over 500Ω you can omit the resistor I suggested and connect the pins direct to the 5.1VS
After looking closer at the board, DIM_PWM_SIGNAL may not be used on this model and the backlight should come on with the BL_ON/OFF line.
This board uses pulldown resistors so without the main connected the power supply stays in the OFF/standby state

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

R327A is 1 k ohm and R341 is less than one ohm and it has only one black stripe.

[R_J]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

Ok, you won't need a resistor between REMOTE_ON/OFF, so connecting CN202 pin 11 to the 5.1VSB directly will be ok, that will turn the power supply on. I'm just not sure about the BL_ON but you may not need a resistor for it either.

[budm]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

The reason I always suggest to use the resistors for force on incase you jump the 5.1VSB to the wrong pin.

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

I had a 4 pack of 560 ohm resistors, I have connected them with small alligator clip leads and this did force on the power supply and backlights are on now...I did have backlights prior to this test but the tv would power itself back off in about 2 to 3 seconds...now that I have these resistors in place what would be the next step???? I tried to see if all led's are on but it's hard to tell from the back side, but it appears as if they are.

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

Here's how I jumped in the resistors. Yellow 5.1 VSB supply to resistors. red to pins 11 & 12 used one resistor here, and green to touch one side of pin 14 being careful not to touch pin 13.

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

The reason I always suggest to use the resistors for force on incase you jump the 5.1VSB to the wrong pin.

Thanks Bud.

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

Thanks Bud.

Thanks budm

[MisterD]

Re: Vizio M370NV Powers on for 2 seconds then shuts down

Your isolation transformer/with switched output, won't help, this power supply is universal input 100~240vac input and it will have no real effect on the power supply voltages.
You should be able to check the power supply/backlights by:
disconnect the cable between main and power supply boards
using a few 470Ω~1kΩ resistor
Connect one between 5.1VSB and REMOTE_ON/OFF (this should turn on the power supply)
Connect one between 5.1VSB and BL_ON/OFF (this should turn on the backlight but may need dim signal)
Connect one between 5.1VSB and DIM_PWM_SIGNAL ( this should turn on the backlight)

I had a 4 pack of 560 ohm resistors, I have connected them with small alligator clip leads and this did force on the power supply and backlights are on now...I did have backlights prior to this test but the tv would power itself back off in about 2 to 3 seconds...now that I have these resistors in place what would be the next step???? I tried to see if all led's are on but it's hard to tell from the back side, but it appears as if they are.