Vizio E370VT

[jason424]

Have another Vizio E370VT that won't turn on when power applied. Was told it was working previously, but now it won't turn on at all, just steady amber standby light.

Unplugging the main and trying the power button again results in the same, no response.

I feel like I should be getting some kind of reading across the On/Off and Dim. Typically I thought I usually got .1 on the others I had.

On/Off: 0
Dim: 0
+12v: 26.4
+12v: 26.4
Gnd: 0.00
Gnd: 0.00
Gnd: 0.00
+24: 54.9
+24: 54.9
PS_ON: 9.9
5v+ 10.9
5v: 10.9
NC: 0

[budm]

Re: Vizio E370VT

1) Check your meter's batteries. No way those Voltages can be that high.
2) Make sure meter is set to read V DC.

[jason424]

Re: Vizio E370VT

Sorry, you're correct...meter was on AC, not DC.

On/Off: 0-.1 (was going back and forth)
Dim: .1
+12v: 12.3
+12v: 12.3
Gnd: 0.00
Gnd: 0.00
Gnd: 0.00
+24: 25.3
+24: 25.3
PS_ON: 4.8
5v+ 5.2
5v: 5.2
NC: 0

[nomoresonys]

Re: Vizio E370VT

Have another Vizio E370VT that won't turn on when power applied. Was told it was working previously, but now it won't turn on at all, just steady amber standby light.

Unplugging the main and trying the power button again results in the same, no response.

I feel like I should be getting some kind of reading across the On/Off and Dim. Typically I thought I usually got .1 on the others I had.

On/Off: 0
Dim: 0
+12v: 26.4
+12v: 26.4
Gnd: 0.00
Gnd: 0.00
Gnd: 0.00
+24: 54.9
+24: 54.9
PS_ON: 9.9
5v+ 10.9
5v: 10.9
NC: 0

Are those readings both in standby and when you hit the power on? if so, looking like the mainboard isn't sending proper signal/s for turning on, could try unpug powerboard from mainboard and force on powerboard with resistor/s and see if you have backlights.

[jason424]

Re: Vizio E370VT

Yes, they don't fluctuate at all when I press the power button.
I should clarify, the results you quoted above are incorrect. I wasn't able to edit that post any longer so my post #3 has the correct readings.

[jason424]

Re: Vizio E370VT

Are those readings both in standby and when you hit the power on? if so, looking like the mainboard isn't sending proper signal/s for turning on, could try unpug powerboard from mainboard and force on powerboard with resistor/s and see if you have backlights.

Could you explain how to force the powerboard on using resistors? I do have an extra powerboard and mainboard for this set (TV still reacts the same no matter which boards are installed so not sure if any are good) so I am happy to experiment as needed.

[nomoresonys]

Re: Vizio E370VT

Honestly I haven't done this model, I think the resistor should protect from shorting anything, guessing use 1 k resistor from ps-on to 5 volt standby and another resistor from 5 volt standby to on/off?? bet one of the vizio guys here know exact method.

[R_J]

Re: Vizio E370VT

Your voltages seem to be ok on the power supply, You could be missing the backlight, have you tried looking at the screen using a flashlight to see if there is any image? you may need to press the menu button to bring up anything if its not on a working source.
The on/off (and dim) controls the backlight from the main board, The two control pins pass through the power supply but do not control the power supply, they only control the inverter

[budm]

Re: Vizio E370VT

On/Off: 0-.1 (was going back and forth): Missing BL-ON = No Backlights.
Dim: .1: Missing Dimming control
+12v: 12.3
+12v: 12.3
Gnd: 0.00
Gnd: 0.00
Gnd: 0.00
+24: 25.3
+24: 25.3
PS_ON: 4.8: PS-ON is fine otherwise you will not have the switched 12V, 24V
5v+ 5.2
5v: 5.2
NC: 0
You can try forcing on backlights by disconnecting the ON/OFF and DIM wires going back to the main board first then use two 1K resistors; one between 5.2V standby power supply pin and ON/OFF pin and another one between 5.2V standby power supply pin and the Dim pin.

[jason424]

Re: Vizio E370VT

On/Off: 0-.1 (was going back and forth): Missing BL-ON = No Backlights.
Dim: .1: Missing Dimming control
+12v: 12.3
+12v: 12.3
Gnd: 0.00
Gnd: 0.00
Gnd: 0.00
+24: 25.3
+24: 25.3
PS_ON: 4.8: PS-ON is fine otherwise you will not have the switched 12V, 24V
5v+ 5.2
5v: 5.2
NC: 0
You can try forcing on backlights by disconnecting the ON/OFF and DIM wires going back to the main board first then use two 1K resistors; one between 5.2V standby power supply pin and ON/OFF pin and another one between 5.2V standby power supply pin and the Dim pin.

So that worked, I have backlights!
So...what does that mean?!

[budm]

Re: Vizio E370VT

So you just disconnect just the two wires going to the main board and you get the backlghts to come on OK, if there is no other problems with the main board, T-COn board then you should see pictures on the screen, hear the sound and everything else; if not then you have more than two problems (missing BL-ON and Dim) on the main board.

[jason424]

Re: Vizio E370VT

Yeah I don't get any images on the screen (tried menu for example and volume up/down). I tried a second main board, which I received from TV Parts Central and same thing. I also have another LED driver board which I tried swapping out and still the same.

[budm]

Re: Vizio E370VT

Are you 100% sure that the replacement main board is good?

[jason424]

Re: Vizio E370VT

Are you 100% sure that the replacement main board is good?

No, I can only take their word for it. Maybe I'll see if I can source another. Not sure if I wanna throw much more $ toward this thing though.

[R_J]

Re: Vizio E370VT

It may be an eeprom issue on the main board, do you have a way to freeze the eprom (U408) on back of main, Either use freeze spray or an inverted can of caned air. Unplug the tv, freeze the ic, then plug in the tv and press power and see if turns on.

[jason424]

Re: Vizio E370VT

Tried canned air and freezing U408 on the back of the main board and plugging in and hit the power button and nothing. Thanks for the idea though!

[nomoresonys]

Re: Vizio E370VT

Maybe send that board back and see if tv parts central will send you another one, it may be faulty, do you get the exact same low/missing voltages with both mainboards?

[jason424]

Re: Vizio E370VT

Are you 100% sure that the replacement main board is good?

Maybe send that board back and see if tv parts central will send you another one, it may be faulty, do you get the exact same low/missing voltages with both mainboards?

I do get the same low voltages with both boards. And I highly doubt they will send me another as this one was received well over 2 years ago when I was working on another E370.

[Unspun01]

Re: Vizio E370VT

This is a vizio mainboard, but looks similar those made by AmTRAN.

Try obtaining Vizio firmware from their website, place the firmware on a correctly formatted USB stick, place usb stick into USB port on TV, then plug TV in and see if the TV automatically installs firmware from USB. You may have to leave the USB plugged in for 10 minutes or more.

I repaired a 32" Panasonic LCD TV a few years ago that had similar design and didn't work despite everything testing ok. Installed firmware via USB and voila!

There may be some LED blinks from green to red, or whatever. I can't remember but try USB update.

These are very similar instructions (from Panasonic, may not work for you)

https://av.jpn.support.panasonic.com...step3_eu3.html

It's worth a shot in case vizio uses similar board as that Panasonic TV used

[budwich]

Re: Vizio E370VT

now that you got backlights, maybe you need to move further along the video path towards the tcon to check things there. Should be some voltage labeling somewhere on the tcon that you can check.... along with any fuses.

of course a picture of the back of the set showing how the cards are connected may help. Depending on the configuration, if 12v is switched at the main, you might want to check that it gets there and then again leaves toward the tcon.