Vizio E371VL Fixed!

[Paul Revere]

I was working on this TV and found the problem after replacing the EEPROM.
Symptoms were would turn on and display dim vizio symbol on the screen. The vizio label would change from amber to white and it would stay running. No display after the initial one on the screen went dark. No menu, sound or picture. Found shorted diode on power supply location D602. Part was labled
MUR460ax.

[tibimakai]

Re: Vizio E371VL Fixed!

I think, that I had this problem with another Vizio and it was the same model, but it would not turn on at all.
I have a VA model now and even by replacing the EEPROM, it still won't turn on.
Backlight comes on, if I force the PS.

[budm]

Re: Vizio E371VL Fixed!

I am curious as to where D602 is in which part of the power supply board.

[tibimakai]

Re: Vizio E371VL Fixed!

On mine, it was the upper left diode in a 45 degree position, next to that red transformer(?).
https://www.badcaps.net/forum/attach...3&d=1383452706

[jscifi]

Re: Vizio E371VL Fixed!

Thank you for posting this it fixed my vizio tv. My vizio logo on screen display was dim too and it would flash for a second and go dark.

[crxguy89]

Re: Vizio E371VL Fixed!

I was working on this TV and found the problem after replacing the EEPROM.
Symptoms were would turn on and display dim vizio symbol on the screen. The vizio label would change from amber to white and it would stay running. No display after the initial one on the screen went dark. No menu, sound or picture. Found shorted diode on power supply location D602. Part was labled
MUR460ax.

Mine is doing something similar. I tried to test this diode. I have a meter with a diode test setting. It has been a while since I have done anything board level. This diode was reading .4 volts something is that bad? I thought a good one should read between .5 and .8 volts. It was showing 'open' in reverse. Like I said... I am rusty. Thanks in advance.

[budm]

Re: Vizio E371VL Fixed!

The diode is Shottky diode so the Vf is less than typical Diode.
Can you show us the pictures of where this D602 is? I would think if the power supply has shorted diode the power supply will be in the shutdown protection mode.

[vinceroger69]

Re: Vizio E371VL Fixed!

thats probaly ok if it reads in one direction only whats the fault with uour set?

[budm]

Re: Vizio E371VL Fixed!

BTW, there are more than one version of this TV model.
http://www.shopjimmy.com/catalogsear...q=Vizio+E371VL
If I look at the correct board, the D602 is in the PFC Voltage booster section.
So are you getting the boosted Voltage from the main power supply?

[ReeceyBurger123]

Re: Vizio E371VL Fixed!

Same issue with Vestel power supplies too, MUR460 pfc diode blows causes low standby voltage and makes the set look dead.

[crxguy89]

Re: Vizio E371VL Fixed!

The diode is Shottky diode so the Vf is less than typical Diode.
Can you show us the pictures of where this D602 is? I would think if the power supply has shorted diode the power supply will be in the shutdown protection mode.

They symptoms are:

I plug in the TV. The Vizio light is amber. I turn on the power button and the Vizio light goes white and nothing else happens. No screen, no sound, etc... No buttons are responsive. Power button will NOT turn the set off. I included pics of the boards. Their board numbers. And the diode in question.

[budm]

Re: Vizio E371VL Fixed!

OK, that diode is part of the PFC Voltage booster circuit, if the circuit is ok then when you turn on the TV the Voltage between the two legs of the main filter cap should be close to 400VDC.

[crxguy89]

Re: Vizio E371VL Fixed!

OK, that diode is part of the PFC Voltage booster circuit, if the circuit is ok then when you turn on the TV the Voltage between the two legs of the main filter cap should be close to 400VDC.

Thanks Budm. Do you know if there are test points for it on the front of board?

Thanks again.

[budm]

Re: Vizio E371VL Fixed!

Thanks Budm. Do you know if there are test points for it on the front of board?

Thanks again.

OK, I trace out the connections on the bottom side of the board, the Cathode of diode D602 and D606 are connected to the + leg of the main cap, the jumper wire JW10 and JW14 are connected to the - leg of the main filter cap so you can easily measured the dcv on the main filter cap from the top side of the board.
So Red probe on the Cathode (banded side), Black probe on JW14.

[crxguy89]

Re: Vizio E371VL Fixed!

I have 393 VDC in this circuit. I have no idea where to go from here. Can you tell me what I should be looking for from here.

[budm]

Re: Vizio E371VL Fixed!

The PFC is OK.
From your post 'No buttons are responsive. Power button will NOT turn the set off. I included pics of the boards.' It points to the problem on the main board or something is locking out the main board, but at this point we need to know what DCV you have on the connector of the power supply board that goes to the main board first.
As you can see that there are labels for each pin of the connector, we need to know what the Voltages are, make sure to report the pin name follow by the Voltage reading for each pin.

[vinceroger69]

Re: Vizio E371VL Fixed!

if all of the voltages test ok it maybe another vizio eeprom issue

[crxguy89]

Re: Vizio E371VL Fixed!

The PFC is OK.
From your post 'No buttons are responsive. Power button will NOT turn the set off. I included pics of the boards.' It points to the problem on the main board or something is locking out the main board, but at this point we need to know what DCV you have on the connector of the power supply board that goes to the main board first.
As you can see that there are labels for each pin of the connector, we need to know what the Voltages are, make sure to report the pin name follow by the Voltage reading for each pin.

Here are the results.
(Some of these names may be wrong. They were hard to read)
VBR_R = 3.3VDC
Status = .25VDC
on/off = .3VDC
on/off = 3.3VDC
12V = 12VDC
12V = 12VDC
12V = 12VDC
GND = Closed circuit to Chasis Ground
GND = Closed circuit to Chasis Ground
GND = Closed circuit to Chasis Ground
GND = Closed circuit to Chasis Ground
5VSB = 5VDC
5VSB = 5VDC
5VSB = 5VDC

Let me know what you make of all this. Thank

[budm]

Re: Vizio E371VL Fixed!

From the look of it, the two ON/OFF pins, one of them has to be for the PS-ON for turning on the rest of the power supply and it is working (the one with 3.3VDC) otherwise you will not have that PFC Boosted Voltage on the main cap, the other ON/OFF (0.3VDC) is probably for the BL-ON for turning on the backlights and it is not working because it is <1VDC.
So the main board is the problem at this point.
There are fuses and Voltage regulator ICs on the main board that you should check.

[crxguy89]

Re: Vizio E371VL Fixed!

From the look of it, the two ON/OFF pins, one of them has to be for the PS-ON for turning on the rest of the power supply and it is working (the one with 3.3VDC) otherwise you will not have that PFC Boosted Voltage on the main cap, the other ON/OFF (0.3VDC) is probably for the BL-ON for turning on the backlights and it is not working because it is <1VDC.
So the main board is the problem at this point.
There are fuses and Voltage regulator ICs on the main board that you should check.

Thanks Bud.

The fuses I can check. The ICs. I do not know how nor would I know what is a good range for them to be in.

Should I just replace the main board? I would rather try to repair....

Any suggestions?