Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

[triplefour]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

budm you saw that i explained i measured the EN pin as you asked and it never spikes?
and ok i will get that picture

[budwich]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

triplefour.... budm's picture shows the '220" or something resistor but your picture shows a "0 ohm" one which is either a jumper or fuse depending on design. Are you checking the "EN" on the side closest to connector?

[budm]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

budm you saw that i explained i measured the EN pin as you asked and it never spikes?
and ok i will get that picture

Sorry, the thread is getting long and it is hard for me to keep track.

[triplefour]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

heres some pics.. i wish there could be more posts per page

[budm]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

Does this TV have WiFi module?
http://www.shopjimmy.com/vizio-317ga...ss-adapter.htm
http://www.shopjimmy.com/catalogsear...zio+P502UI-B1E
If it does, then try disconnecting the cable going back to the main board to see what happen.

[al1415]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

dimms down to a black screen, even using flash light nothing on screen shows nothing.

[triplefour]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

it does have the wifi module and ive already tried that but didnt mention it. it doesnt change anything

[budm]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

This is the tough one.

[al1415]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

Sorry my last post #66 went with #59. same here disconnecting WIFI does nothing.

[al1415]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

Budm I am going to back out for now as we have 2 different sorta issues, mine when lights dim down instead of holding they go totally out. He has incorrect voltages. Do not want you to get confused anymore than what you are. I just need to find out what control's the dimming aspect. Maybe the same buck regulator does do that i do not know for sure or maybe something on main board controls that signal. And I am getting a head ache from all this...LOL

[al1415]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

If you need more voltage comparison i will still be watch this thread. Always learning something.

[budm]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

Connector CN805 on the LED driver board is the one that gets the BL-ON and dimming control signals from the main board.
I can see 6 small signal traces.
Can you read the P/N of the LED driver IC's (4 of them)? I.E. U301 to find the spec sheet to find out which pin is for dimming control.

[triplefour]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

i know it doesnt apply to my problem (yet) but im happy to help
i think i see
AS3820E H
1421XBC

[triplefour]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

al1415 could you verify the voltage you have on the ENable pin (pin2) of IC804? easiest way to get is to measure either side of R8219
and also if you can, the voltage on C8067 (which is connected to the SS pin)
just to see how this IC is actually working, if i am supposed to have voltage at the enable pin for "normal" operation.
thank you

[al1415]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

R8219=4.1
c8067=1.8

[al1415]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

Budm the chip numbers are:1Z690l2 and ZA4S16. Look for data sheet could not find by either number.

[triplefour]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

al1415 thanks, so i guess the enable pin DOES have to be on..as well as the SS
im thinking those voltages must come from the mainboard and correspond to the 2 im missing on CN805

[budm]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

i know it doesnt apply to my problem (yet) but im happy to help
i think i see
AS3820E H
1421XBC

https://www.dialog-semiconductor.com/products/as3820

[budm]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

Budm the chip numbers are:1Z690l2 and ZA4S16. Look for data sheet could not find by either number.

Your P/N is not same tripefour in post 73
https://www.dialog-semiconductor.com/products/as3820

[al1415]

Re: Vizio P502UI-B1E has no backlight, no voltage from driver board to LED's

Found this link that gave more info on chip..