Vizio 60" E601i-A3 Backlight Issue

[pete7863]

I have a Vizio E601i-A3 LCD TV. Last night when I turned it on, the picture came on as well as the audio, but the backlight was very noticeably flickering across the entire screen. After cycling power to the TV, subsequent startups produced slightly different results (no picture, or at least no visible picture - the backlight seemed to be turning off on its own). I searched through the forum and saw some other similar threads related to this specific TV, but they did not appear to have the same symptoms as my TV (see PREVIOUS THREAD).

At this point, when I power on the TV, the backlight turns on for a few seconds and then shuts off entirely. During the period in which it is on, I am able to verify ~85VDC (~7 VAC of ripple) on each of the 4 outputs of connector CN301 (appears to be the header for the power board to the LED backlights). In addition to this, sometimes the tv will seem to turn itself on and leave the backlight on (but it is still flickering).

I was able to gather the following voltage readings from connector CN201 (appears to be the header for the power board to the main board).
Pin__Label________TV off volts__TV on volts
1____3.3V________3.357______3.343
2____AC-DET______3.445______3.433
3____PS-ON_______0.097______3.309
4____12V-AU______0.568______12.31
5____GND_________0.000_____0.000
6____GND_________0.000_____0.000
7____GND_________0.000_____0.000
8____12V REG______0.4_______12.30
9____12V REG______0.4_______12.31
10___BL-ERR_______0.008_____3.351
11___LED-ON______0.000______3.031
12___LED-BR______0.006______0.440
13___NC__________0.000______0.000
14___T2V T CON____0.104______12.31
15___T CON_ON____0.000______3.222

Any help is greatly appreciated!

[budm]

Re: Vizio 60" E601i-A3 Backlight Issue

https://www.shopjimmy.com/vizio-09-6...-led-board.htm
Is that the exact board used in your TV?
Can I see good clear pictures of the whole backside of the TV showing all the board?
You have Four LED strings, the LED connector shows Plus (Anode) pin and Minus (Cathode return) pin for each LED string.
You need to put meter in 200V DC range, then keep black probe of the meter on the chassis, then put red probe, I.E. on the VLED1 - 1+ then turn the TV on while watching the meter to see how high it goes up to and then wait about 5 seconds to see how low it goes down to, record the results, then turn off the TV and repeat the same test on the other 7 pins of the LED connector. It is important that you follow the procedures and the request.

[pete7863]

Re: Vizio 60" E601i-A3 Backlight Issue

Hello budm, thanks for reaching out!

The board you referenced looks very similar, but I believe I have the older revision (I have the "VLED1-2-" typo in the silkscreen). I have attached images of the boards for reference below.

I placed my DMM per your procedure (with the LEDs connected) and got the following results. Please note that after 5-10 seconds the backlight flickers brighter (corresponding to a higher quick peak voltage) and then immediately turns off. After the backlight gets turned off, all of the voltages go to 0 within a second or two (they ramp down during that period, but it's hard to put a number to it).

PIN_________________VOLTAGE AFTER TURN ON_____VOLTAGE PEAK BEFORE SHUTOFF
VLED1-2- (VLED1-1+)__85.9______________________97.2
VLED1-1-____________0_________________________0
VLED1-2+____________0________________________0
VLED1-2-____________-86.1_____________________-107.2
VLED2-1+____________86.2______________________104.0
VLED2-1-____________0_________________________0
VLED2-2+____________0________________________0
VLED2-2-____________-86.1_____________________-101.6

Feel free to let me know if there are any other measurements that you think would be helpful.

[pete7863]

Re: Vizio 60" E601i-A3 Backlight Issue

After poking around with a DMM some more, it appears that the backlight voltage has some AC ripple on it (~7 volts) and perhaps that is what is making the screen appear like it is flickering for the brief period that it is on (<5 seconds). It seems like the main board is able to sense something is wrong (perhaps an overvoltage condition as right before it turns off the voltage spikes) and ends up shutting off the backlight. I'm not sure what is causing the ripple since I haven't been able to fully reverse engineer the board (there are some integrated circuits that I can't read any part numbers off of and I am unable to look up info on the transformers). However, I am open to tinkering with it some more if anyone has any suggestions. Additionally, if ordering a replacement board off of shopjimmy seems like the right call (would just like some input to know if I am targeting the correct board), I am open to that option as well.

[Diah]

Re: Vizio 60" E601i-A3 Backlight Issue

your TV are with edge LED backlight. not as mentioned before 4 strips. it use Vizio's Razor LED system which are one lie of VIZIO ... most issue by log in service menu and make hard reset or.. update it to last firmware getting rid of this eyes looking issue. if not then there hardware issue at LEDs

[budm]

Re: Vizio 60" E601i-A3 Backlight Issue

"12___LED-BR______0.006______0.440"
Monitor that Dimming control pin 12 when turn on the TV to see if it is going up and down in sync with the flickering or not.
You can also try testing the power supply/LED driver by using force on method.

[pete7863]

Re: Vizio 60" E601i-A3 Backlight Issue

I checked the LED-BR pin while on and even though it sits at 0.440 VDC it has 1.035 VAC of ripple. This AC ripple measures 120 Hz on my multimeter. I went back to the LED connector (CN301) and the LED voltage has a frequency of 120 Hz as well. I assume this is not normal. Would this lead you to believe that the issue is coming from the main board?

Additionally, what is the "force on" method? Is there a way to input signals into CN201 to accomplish this (or something else)?

[budm]

Re: Vizio 60" E601i-A3 Backlight Issue

LED--BR is PWM that is what I expect to see, typical PWM for backlights control is around 200Hz. The LED's are not driven by steady current, the control element (I.E. MOSFET) for maintaining the constant current is driven by PWM control signal.
To force on the power supply and the LED backlights circuit, you will need to disconnect cable going to the main board first, the use resistor (330 ~ 470 Ohms) between the 3.3V Standby power supply output pin and the PS-ON pin, and then another same value resistor between 3.3V Standby power supply and the LED-ON pin, then plug the AC plug into the AC outlet, the backlights should then come on and stays on as long as the TV is plugged into the AC outlet. If the backlights still does not come on then you may need another resistor between 3.3V Standby power supply and the LED-BR.

https://www.tftcentral.co.uk/article...modulation.htm

[pete7863]

Re: Vizio 60" E601i-A3 Backlight Issue

I had to use all 3 resistors to get the backlight to come on. When I plugged in the AC power, the backlight was still flickering and the voltage on the pairs of pins of CN301 was around 105VDC with 4VAC of ripple. Let me know if you have any other useful measurements to take while in this state.

[pete7863]

Re: Vizio 60" E601i-A3 Backlight Issue

Is the behavior above indicative of bad backlight LEDs, or a bad driver board? Any advice on troubleshooting further to determine this?

[pete7863]

Re: Vizio 60" E601i-A3 Backlight Issue

My apologies in advance as I hate to triple post. However, I’m torn on where to go next to troubleshoot. Is there a simple way at this point to tell if the LEDs are at fault or the board is at fault? Would it be a bad idea to chain 9 or 10 9 V batteries together to drive the LED outputs individually (not sure if the absence of current limiting would be an issue). Thanks for all of your assistance so far!

[budm]

Re: Vizio 60" E601i-A3 Backlight Issue

I am still thinking about the 0V readings on 4 pins of the connector and trying to trace out the circuit.
The LED driver IC seems to under the white glue on the bottom side of the board. Can you remove the glue so you can read the IC P/N?

[budm]

Re: Vizio 60" E601i-A3 Backlight Issue

I found this: https://www.badcaps.net/forum/showth...light=E601i-A3

[pete7863]

Re: Vizio 60" E601i-A3 Backlight Issue

I was out on vacation this last week, but decided to order a repair power board off shop jimmy. The board arrived yesterday afternoon and I installed it this evening. Once I swapped the boards, the issue went away. Going off of this, it appears that the original power board I had went belly up (and the backlight LEDs were fine). I’m tempted to dig deeper to try and compare the old and new board, but it’s football season, and I hate being down my big tv! Thanks again to all that assisted (especially you budm)!!!

[budm]

Re: Vizio 60" E601i-A3 Backlight Issue

Glad to hear the new power supply board fixed the problem, I hope when you have time you can take some Voltage readings at the LED connector so will have it as reference for future repair.

[lpatety]

Re: Vizio 60" E601i-A3 Backlight Issue

LED--BR is PWM that is what I expect to see, typical PWM for backlights control is around 200Hz. The LED's are not driven by steady current, the control element (I.E. MOSFET) for maintaining the constant current is driven by PWM control signal.
To force on the power supply and the LED backlights circuit, you will need to disconnect cable going to the main board first, the use resistor (330 ~ 470 Ohms) between the 3.3V Standby power supply output pin and the PS-ON pin, and then another same value resistor between 3.3V Standby power supply and the LED-ON pin, then plug the AC plug into the AC outlet, the backlights should then come on and stays on as long as the TV is plugged into the AC outlet. If the backlights still does not come on then you may need another resistor between 3.3V Standby power supply and the LED-BR.

https://www.tftcentral.co.uk/article...modulation.htm

Hello, my problem is that the LEDs turn on and off, I did the test as you indicate to force the LEDs to turn on, and they turn on and off immediately, I used a led strip tester and each of them light up well. Can I run another test to make sure it's the power supply before I buy it? My TV is a Vizio E601i-A3