VIZIO E500i-A0 No Picture With Sound

[zukdj]

Re: VIZIO E500i-A0 No Picture With Sound

I am perplexed, the power rolls 120-130 on LED 1 and LED 2 positive side (+) whether backlights are plugged in to the power supply or not. When they are plugged in I would think the power would be reduced per a ShopJimmy video.

[budm]

Re: VIZIO E500i-A0 No Picture With Sound

It will reduce when the load is connected, so if you have open LEDs then the L+ will show the same reading with or without the LEDs connector in place, then the Voltage will drop down when the over Voltage protection kicks in.

[budm]

Re: VIZIO E500i-A0 No Picture With Sound

BTW, you also need to check the Dimming control line to make it is OK, that can also cause strobing problem or no backlights.

[zukdj]

Re: VIZIO E500i-A0 No Picture With Sound

Where is that dimming control line please and how do I check that? How long does over voltage protection take to kick in?

[budm]

Re: VIZIO E500i-A0 No Picture With Sound

Where is that dimming control line please and how do I check that? How long does over voltage protection take to kick in?

It only take seconds for the protection circuit to kick in, but the charge on the caps may stay for 3~10 seconds since there is no loads to discharge them.
You have to look at the board connector to look for the labels for the pins.

[zukdj]

Re: VIZIO E500i-A0 No Picture With Sound

I never saw a discharge, same constant after 4 mins on

[zukdj]

Re: VIZIO E500i-A0 No Picture With Sound

BudM, what I meant to say is I never saw a decrease in voltage, backlights unplugged or plugged in. A bit of a newbie here so please be patient with me.

[budm]

Re: VIZIO E500i-A0 No Picture With Sound

So it stays at 120V or so? What do you see if you leave the probe on the L+ and turn the TV on, does it jump up much higher than 120V?

[zukdj]

Re: VIZIO E500i-A0 No Picture With Sound

Obviously there is no reading until the TV is on, then it rolls between 120-130v, it doesn't matter either way, backlight plugged in or unplugged, same reading although, and this may be important, the negative LED side has a low voltage reading when the backlight is plugged in, I think -1 rolls between 50-39v and -2 rolls between 30-18v. I would assume the negative side should never have a reading?

[zukdj]

Re: VIZIO E500i-A0 No Picture With Sound

Let me go probe it and turn on the TV to see what happens...

[zukdj]

Re: VIZIO E500i-A0 No Picture With Sound

Probed it, turned on the power, hits 130 and rolls between 130 and 120 consistently. I still am perplexed about power on the negative side when the backlights are plugged in.

[budm]

Re: VIZIO E500i-A0 No Picture With Sound

If you look at your board:
Vizio 0500-0605-0280 (FSP155-2PSZ01) Power Supply / LED Board
http://www.shopjimmy.com/vizio-0500-...t-inverter.htm
You can see that it has TWO LED string drive circuit, MOSFET Q302 for the boost converter, MOSFET Q303 is the PWM controlled to maintain constant current through the LED string set #1, Q402, Q403 are for the second LED string driver.
The panel has 12 strips of LEDs, 6 strips (each strip has 5 LEDs) are connected in series to form one long string consist of 30 LEDs, so you have two set of the LED strings and each one are driven by its own driver.

LG LC500DUG-JFR1 LED Strips - 12 Strips & 1 Board Vizio E500I-A0 E500D-A0
http://www.shopjimmy.com/lg-lc500dug...ps-1-board.htm
The Anode (L+) of the first set of the string is connected to the Boost converter output, the Cathode return (L-) of the string is connect to the Drain pin of the PWM controlled MOSFET, the Source pin is connected to the current sensing resistors, the other end of the resistors are connected to GND return circuit, the Voltage drops on the current sensing resistors are used as the feedback to maintain the constant current through the LED string.
So each string has 30 LEDs, so the minimum power supply Voltage has to be at least 30 x 3V = 90V + V drops on the MOSFET, you have 120~130V so that is more than enough to drive the LEDs.

"I think -1 rolls between 50-39v and -2 rolls between 30-18v." This pointed out that you do have LEDs problem because the L- should show about the same readings.

Pictures provided by SHOPJIMMY.

[zukdj]

Re: VIZIO E500i-A0 No Picture With Sound

OK, not that it matters anyhow at this point because nobody has the LED kit available, just my luck. ShopJimmy offers the complete kit for $70 but it is out of stock and has been for a while. I suppose I could dig deeper, would I be able to tell what LED's are bad by looking at them?

[zukdj]

Re: VIZIO E500i-A0 No Picture With Sound

BudM, I have one more question, can I power those LED's any other way at the plug and take the power supply completely out of the equation? Then I could simply look at the screen and see if I have any "dark" areas. Just a thought, not sure being somewhat of a newbie.

[budm]

Re: VIZIO E500i-A0 No Picture With Sound

You can get bench power supply with current regulation (constant current source) that can go up to 100vdc, or you can buy LED tester from shopjimmy or EBay.

[desho1]

Re: VIZIO E500i-A0 No Picture With Sound

Vizio E500i-A0 backlight on 1/2 second off 2 seconds have picture w/ flashlight and sound.

[nomoresonys]

Re: VIZIO E500i-A0 No Picture With Sound

See if you can locate a backlight NOT brightness setting and turn it down to 0 or so, see if any symptoms change. No need to post your problem on many threads, we can see it.

[desho1]

Re: VIZIO E500i-A0 No Picture With Sound

Vizio E500i-A0 backlight on 1/2 second off 2 seconds have picture w/ flashlight and sound.

All of the leds flash on and off with the fluctuation, the voltage fluctuation is the same without the leds plugged in, All main board to psu voltages are good with stby and bl on, I tried turning down both back light and brightness without change, laser thermometer is registering 175 degrees on primary mosfet and circuitry to optocoupler, caps all look good.

[nomoresonys]

Re: VIZIO E500i-A0 No Picture With Sound

Maybe also check the bottom of your powerboard for bad/cold/loose/cracked solder joints, look closely sometimes they look good but are not. look at joints of components on heatsinks and transformer joints, they take the most abuse.

[R_J]

Re: VIZIO E500i-A0 No Picture With Sound

You very likely have one ore two bad led's. I suspect one or more led's on a string are shorted, causing an over current condition and shutdown of the backlights.
If a string was open you would likely read 0 volts on the LED1/2-