Need schematic for Visio LC420

[jkb242]

Before I come to request assistance, I would like to do my own due diligence fin troubleshooting this dead set. If someone has a schematic of the power board or the entire set I would greatly appreciate so very much. I love this forum and site it's the only one I follow for years.

Thanks so very much in advance!,

[budm]

Re: Need schematic for Visio LC420

2: that does not look like Vizio TV model number. That sounds more like the LCD panel model number.
2: if you upload good clear straight shot high-res pictures of the whole Top and Bottom side of the board then you may get more help.
3: I doubt that we will find the schematic of the power supply board, it is made by the third party.
What Voltages did you test on the power supply board so far?
The more details you provide the more help you will get.

[jkb242]

Re: Need schematic for Visio LC420

Thanks Bubm, I remember your excellent troubleshooting guide. Thanks for referencing it again for me and let me get some measurements and pictures read for reply.

Thanks!

[budm]

Re: Need schematic for Visio LC420

So what is the correct TV model?

[jkb242]

Re: Need schematic for Visio LC420

It’s an LED E series E420 VL
Have 5v SB, 12vdc. No 24vdc. No switched PSon 5v.

Going to take photos and post. Fron Visio light is amber and not changing to white, confirming no PSON 5v. So no PSON SIGNAL FROM system. Have not connected a load to PS check 12vdc but do not believe I have a 24v rail to test. Would love a schematic to do further troubleshooting but happy to have your valuable input and assistance.

I have reviewed the excellent document you authored as a basis for proving the above.

[jetadm123]

Re: Need schematic for Visio LC420

I believe the E420VL uses ccfl backlighting and not LED. You might want to provide some good photos of the boards and how they're all connected.

[jkb242]

Re: Need schematic for Visio LC420

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Please advise if these photos contain sufficient detail for assistance.

Thanks

[jkb242]

Re: Need schematic for Visio LC420

I believe the E420VL uses ccfl backlighting and not LED. You might want to provide some good photos of the boards and how they're all connected.

Just uploaded please advise regarding detail.

Thanks

[nomoresonys]

Re: Need schematic for Visio LC420

http://www.shopjimmy.com/vizio-0500-...upply-unit.htm pic. of powersupply board if that's it.

[jkb242]

Re: Need schematic for Visio LC420

I was wondering with no PSON SIGNAL, audio or BL, would removing the ribbon connections from the TCon/system board to the BL lamps allow some isolation of the trouble to determine if PSON and audio could then be rechecked.

None of the SM FUSES are blown and there are no suspicious visual capacitor concerns to indication gassing or leakage.

[budm]

Re: Need schematic for Visio LC420

You have power supply/inverter board combo for CCFL backlights.
The connector on the power supply that goes to the main board has lable for each pin, can you please provide the DC V readings for each one of those pin.
You also have to fuses on the main board close to the connector that goes back to the power supply board, please check the DC V at both ends of the fuse with ref. to the chassis GND, one should show 5V and another one is for switched 12V.
You also have some LDO Voltage regulator IC's on the main board that you should check.
Did you look at shopjimmy to see if they have EEPROM for this model?

[jkb242]

Re: Need schematic for Visio LC420

http://www.shopjimmy.com/vizio-0500-...upply-unit.htm pic. of powersupply board if that's it.

Thanks for the link to SJ regarding the parts. I haven't been able to determine why I am not seeing any PSON signal to the power supply. Since I believe this signal comes from the system/TCON board, this could be the source of the failure. Is there any way to momentarily connect the 5vSB to the PSON lead to see if the set will start without damage to the system board?

[budm]

Re: Need schematic for Visio LC420

To force on the power supply, you MUST disconnect the wires (I.E. PS-ON, BL-ON) going back to the main board first otherwise you will damage the main board.

[nomoresonys]

Re: Need schematic for Visio LC420

https://www.youtube.com/watch?v=mUvclBfaMXg
Powersupply testing, you don't have to remove the board from the tv tho, just disconnect all the other boards.

[jkb242]

Re: Need schematic for Visio LC420

You have power supply/inverter board combo for CCFL backlights.
The connector on the power supply that goes to the main board has lable for each pin, can you please provide the DC V readings for each one of those pin.
You also have to fuses on the main board close to the connector that goes back to the power supply board, please check the DC V at both ends of the fuse with ref. to the chassis GND, one should show 5V and another one is for switched 12V.
You also have some LDO Voltage regulator IC's on the main board that you should check.
Did you look at shopjimmy to see if they have EEPROM for this model?

Burn,

Per the above attaching picture of power board connector to system board.

Pin 1 3vdc
Pin 4 1.6vdc
Pins5-7 12.2vdc
Pins 8-11 0vdc
Pins 12-15 5.2vdc

160μf cap on power board 325vdc
All fuses on system and power board good.
Removed HDMI chip since customer reported no working HDMI ports before set set died, thinking possibility the IC MIGHT BE SHORTED.

Please let me know if I have provided you sufficient information to continue your assistance

[jkb242]

Re: Need schematic for Visio LC420

You have power supply/inverter board combo for CCFL backlights.
The connector on the power supply that goes to the main board has lable for each pin, can you please provide the DC V readings for each one of those pin.
You also have to fuses on the main board close to the connector that goes back to the power supply board, please check the DC V at both ends of the fuse with ref. to the chassis GND, one should show 5V and another one is for switched 12V.
You also have some LDO Voltage regulator IC's on the main board that you should check.
Did you look at shopjimmy to see if they have EEPROM for this model?

Did you see the pictures I just attached as requested?

[nomoresonys]

Re: Need schematic for Visio LC420

Thanks for the link to SJ regarding the parts. I haven't been able to determine why I am not seeing any PSON signal to the power supply. Since I believe this signal comes from the system/TCON board, this could be the source of the failure. Is there any way to momentarily connect the 5vSB to the PSON lead to see if the set will start without damage to the system board?

It's that BUT more over it's a good close up pic. of the board, these are what you need to post, front and back.

[jkb242]

Re: Need schematic for Visio LC420

One of the pictures I attempted to post shows the power board to system board connection and labeling of the connector. However since none of these will post for some reason. Beginning with Pin one, the pins are labeled:
5.1VSB PIN1-3 measured 5.2vd
SGND PINS 4-7 measured 0vdc
12V PINS 8-11 measured 12vdc
PSON PIN 12 measured 1.17 vdc
I-ON/OFF PIN 13 measured 0vdc
LAMP PIN 14 measured 0vdc
DIM PIN 15 measured 0vdc

PLEASE DISREGARD THE EARLIER VOLTAGE READINGS POSTED, very sorry for being so sloppy in my reporting. I am still trying to figure out why no none of the pictures are being posted. Thanks so very much. My system board is not available at SJ.

[jkb242]

Re: Need schematic for Visio LC420

Now posting picture of power board connector to main board as a supplement to last post and previous from Budm.

[jkb242]

Re: Need schematic for Visio LC420

Detailed views of power and system boards and inter connection. Please advise if additional informational information is required. Working without a schematic is more difficult for me as I am not that familiar with this set and really appreciate the assistance I am receiving!

Thanks