VIZIO M70-C3 Power Supply?

[CaptGB]

No Back Light, No Sound, No Video The board and red light on the CPU audio out tries to power about a minute. Not sure if it the power supply is the problem. Attached photos of voltages at Power Supply board when powered up and then turned on.

Any Suggestions Welcome.

[nomoresonys]

Re: VIZIO M70-C3 Power Supply?

Looks like your not getting the PS-ON signal from the mainboard.

[CaptGB]

Re: VIZIO M70-C3 Power Supply?

I wasn't sure about the voltages that i was reading -- some looked higher that the board indicated?

[budwich]

Re: VIZIO M70-C3 Power Supply?

you need to measure and record every pin shown in first picture.... with tv off and then tv on... note some change quickly after pressing on so you have to monitor each one during each press on.

[CaptGB]

Re: VIZIO M70-C3 Power Supply?

I will re check and follow up

[CaptGB]

Re: VIZIO M70-C3 Power Supply?

I do have 5.1 v to PS-ON pin 3 first photo on everything else is correct on the first photos

Anything else I need to look at ???

[nomoresonys]

Re: VIZIO M70-C3 Power Supply?

Easy test, with tv unplugged from power, check all the diodes on powerboard, try diode mode, should get a reading in one direction, reverse meter probes, should read 1 or OL if any read off, take out of circuit and test again.

[ngth82]

Re: VIZIO M70-C3 Power Supply?

I wasn't sure about the voltages that i was reading -- some looked higher that the board indicated?

Some of the values that you read indicate "33.8" -- is that in VOLTS or MILLIVOLTS?

[budwich]

Re: VIZIO M70-C3 Power Supply?

I do have 5.1 v to PS-ON pin 3 first photo on everything else is correct on the first photos

Anything else I need to look at ???

You need to check all the pins as print on the board of the first picture and watched closely during power up. You are saying you never see the tcon on signal?

unplug the power cable to the tcon... attempt a power up and check the pins for the 12v.

[CaptGB]

Re: VIZIO M70-C3 Power Supply?

No dc voltage to tcon pin 13 tcon, 14 tcon or 15 Tcon ON when unpluged and applying power to power supply board.

All diode visible on power supply board ck ok

All volts checked dc volts

[neilc6]

Re: VIZIO M70-C3 Power Supply?

Does look like tcon on signal is missing. Vizio M series have bga failures on the main boards. Try heating up the main board with a hair dryer and see if it turns on.

[CaptGB]

Re: VIZIO M70-C3 Power Supply?

I am not getting 12V to any of the T Con pins. I'm not sure if it's the Power supply or Main Board. Does the Power Supply receive a signal back to the Main board to power up T Con???

[R_J]

Re: VIZIO M70-C3 Power Supply?

You will not have any 12V T CON (pins13,4) untill it is turned on by (pin15) T CON_ON
You have +12v on pins 8&9 so the power supply is working.
Does pin3, PS-ON change when the power button is pressed? if it does not, then the main board is likely the problem.

[CaptGB]

Re: VIZIO M70-C3 Power Supply?

I do get 5.1v at PS on when the power button is pressed and red led on main board comes on for a while then flashes about 16 times and shuts down

(sorry I missed writing it down on the top photo)

[R_J]

Re: VIZIO M70-C3 Power Supply?

So in standby, PS-ON is 0 volts and when you press the power button, PS-ON goes to 5v correct?

[CaptGB]

Re: VIZIO M70-C3 Power Supply?

yes correct

[R_J]

Re: VIZIO M70-C3 Power Supply?

So the main board is partly working, it understands the the command from the power button and outputs the PS-ON signal correctly, but it's not outputing the T-CON_ON signal, This could be a bga fault on the main as suggested. It could be that the t-con is not turned on until the backlights are turned on.
So the power supply is working corrctly. I would suspect the main board, you can try heating the large ic under the heatsink and see if the tv comes on. the heating can sometimes temporarly restore the connection.

[CaptGB]

Re: VIZIO M70-C3 Power Supply?

tks for the help!!!

[xcctt]

Re: VIZIO M70-C3 Power Supply?

So the main board is partly working, it understands the the command from the power button and outputs the PS-ON signal correctly, but it's not outputing the T-CON_ON signal, This could be a bga fault on the main as suggested. It could be that the t-con is not turned on until the backlights are turned on.
So the power supply is working corrctly. I would suspect the main board, you can try heating the large ic under the heatsink and see if the tv comes on. the heating can sometimes temporarly restore the connection.

Does this heating lead one to do an additional re-soldering on a specific part of the board or is this a temporary band-aid that has to be done from time to time and that's all she wrote?

[R_J]

Re: VIZIO M70-C3 Power Supply?

Does this heating lead one to do an additional re-soldering on a specific part of the board or is this a temporary band-aid that has to be done from time to time and that's all she wrote?

This heating is on a the large BGA ic, if it works, it just rules out the rest of the tv, but usually is only temporary, to do a proper job the ic needs to be removed, reballed and replaced.