vizio e650i-a2 backlight flashes then turns off

[SS454]

vizio e650i-a2 (LWJAOZBP Serial) led backlight flashes then turns off, has video (via flashlight) and audio.

panel: au optronics T650HVN05.4
72 led total on 12 strips, 6 led per strip wired in three groups of 24 (led driver board has three anode and three cathode pins)
link to datasheet: https://datasheetspdf.com/pdf-file/8.../T650HVN05.4/1

Vizio 56.04219.641G (liteon PA-3231-01WN-LF) Power Supply Unit
https://www.shopjimmy.com/vizio-56-0...-power-supply/

Vizio 55.75J01.001G (91.75J10.004G) Main Board
https://www.shopjimmy.com/vizio-55-7...-for-e650i-a2/

Vizio 55.65T07.C07 (T650HVJ02.0, 65T09-C00) T-Con Board
https://www.shopjimmy.com/vizio-55-6...oard-e650i-a2/

Vizio 55.64S03.DE0 (4H+V3516.001/D) LED Driver Board
https://www.shopjimmy.com/vizio-55-6...-for-e650i-a2/

Vizio T650HVN05.4 LED Backlight Strips
vizio ep-65t01e01-jaa4x 65" led light bar
https://www.shopjimmy.com/vizio-t650...ght-strips-12/

voltages with tv off and plugged in:
====================================
Power Supply
cn203 (12 pins)
pins 1-5 (vddb)= 0v
pins 6-10 (blgnd)
pins 11-12= N/C

cn202 (14 pins)
pins 1-5 (vddb)= 0v
pins 6-10 (blgnd)
pin 11 (lamp_det)= 0v
pin 12 (vblon)= 0v
pin 13= N/C
pin 14 (dim)= 0v

cn201 (4 pins)
pins 1-2 (24v)= 0v
pins 3-4 (gnd is marked on board, but pin 3 is N/C)

cn101 (15 pins)
pins 1-2 (5vsb marked on board, but pin 2 is N/C)= 5.04v
pin 3 (ac_off_det)= .655v
pin 4 (ps_on)= 66mv
pins 5-6 (gnd)
pins 7-8 (5vres marked on board, but no pins connected)
pins 9-10 (gnd marked on board, but pin 10 is N/C)
pins 11-12 (reg_12v)= 0v
pin 13 (vblon)= 0v
pin 14 (dim)= 0v
pin 15 (lamp_det marked on board, but pin is N/C)

led driver board:
cn1 (14 pins)
pins 1-5 (vddb)= 0v
pins 6-10 (blgnd)
pin 11 (det)= 0v
pin 12 (vblon)= 0v
pin 13 (N/C)
pin 14 (e_pwm)= 0v

cn2 (12 pins)
pins 1-5 (vddb)= 0v
pins 6-10 (blgnd)
pins 11-12 (N/C)

cn3 (12 pins to led strips, only uses six wires)
pin 1 (1anode)= 0v
pins 2-3 (N/C)
pin 4 (2cathode)= didn't measure this pin
pin 5 (3anode)= 0v
pins 6-7 (N/C)
pin 8 (4cathode)= didn't measure this pin
pin 9 (5anode)= 0v
pin 10-11 (N/C)
pin 12 (6cathode)= didn't measure this pin
========================================================

voltages with tv on:
====================
Power Supply
cn203 (12 pins)
pins 1-5 (vddb)= 24.68v
pins 6-10 (blgnd)
pins 11-12= N/C

cn202 (14 pins)
pins 1-5 (vddb)= 24.70v
pins 6-10 (blgnd)
pin 11 (lamp_det)= 0v
pin 12 (vblon)= 3.3v
pin 13= N/C
pin 14 (dim)= 2.278v

cn201 (4 pins)
pins 1-2 (24v)= 24.70v
pins 3-4 (gnd is marked on board, but pin 3 is N/C)

cn101 (15 pins)
pins 1-2 (5vsb marked on board, but pin 2 is N/C)= 5.03v
pin 3 (ac_off_det)= .649v
pin 4 (ps_on)= 2.368v
pins 5-6 (gnd)
pins 7-8 (5vres marked on board, but no pins connected)
pins 9-10 (gnd marked on board, but pin 10 is N/C)
pins 11-12 (reg_12v)= 11.82v
pin 13 (vblon)= 3.3v
pin 14 (dim)= 2.278v
pin 15 (lamp_det marked on board, but pin is N/C)

led driver board:
cn1 (14 pins)
pins 1-5 (vddb)= 24.69v
pins 6-10 (blgnd)
pin 11 (det)= 0v
pin 12 (vblon)= 3.3v
pin 13 (N/C)
pin 14 (e_pwm)= 2.278v

cn2 (12 pins)
pins 1-5 (vddb)= 24.69v
pins 6-10 (blgnd)
pins 11-12 (N/C)

cn3 (12 pins to led strips, only uses six wires)
pin 1 (1anode)= 24.41v
pins 2-3 (N/C)
pin 4 (2cathode)= didn't measure this pin
pin 5 (3anode)= 24.41v
pins 6-7 (N/C)
pin 8 (4cathode)= didn't measure this pin
pin 9 (5anode)= 24.41v
pin 10-11 (N/C)
pin 12 (6cathode)= didn't measure this pin
==========================================================

what i have done so far:

only problem i could find on original led driver board was that pin 5 (3anode) did not have any voltage on it.
fuse f2 was blown.

disassemble panel and check each individual led strip (12 of them) using a hp laptop psu with output of 19.28 volts.
all led on each string lit completely.

bought this kit from shopjimmy:
https://www.shopjimmy.com/vizio-e650...air-parts-kit/

fed a full 3.3v to ps_on (with wire to main disconnected, of course) because i thought 2.368v might be too low
(made no difference).

so, long story long ;-) tv acts same as original boards. power comes on and backlight flashes once, then turns off.
flashlight shows image (says "no signal" after displaying vizio logo) and have audio, but nada from backlights.
initial voltage on led driver board cn3 (pins 1,5,and 9) is 84v then dropping and holding at 24v.

the only signal i see that might be a problem is the DET signal, but i don't know. i'm a noob on these led backlit
tv's, so i would appreciate some help from the Wise Ones here on the forum. Thanks! James

[howardc64]

Re: vizio e650i-a2 backlight flashes then turns off

Got one that has no backlight but panel shows vizio logo + no source msg with flash light on power on.

Voltage readings are same as OP except for LED driver board CN3. My pin5 and 9 shows 0v when TV pwr on. (also my dim line is 2.6v)

LED tester shows 63.5v on all 3 strings on CN3 (pin 1+4, pin 5+8, pin 9+12) and light up through rear chassis holes. LED tester shows 300v on pin 1+8, and 1+12. Backlight is 12 LED bars each with 6 3v LEDs. So each of the 3 strings should read 6 LED x 3v x 4 bars = 72v and pin 1+8 should read 2x72v? 1+12 should read 3x72v? See CN3 on first pic for reference.

But probably have open LEDs that yields this reading.

New LED bars are pricy in relation to TV's worth. I see other 65" TV's compatible backlight (12 bar, 6 3v LED/bar) for much cheaper. Any problem using it as long as length/width fits, wired up properly and cut holes on reflector paper where new LEDs are?

[dskall]

Re: vizio e650i-a2 backlight flashes then turns off

As long as you keep same number of led's in each string, you should be OK

[howardc64]

Re: vizio e650i-a2 backlight flashes then turns off

UPDATE

all 3 LED string lights up with 65-66V so I figure there aren't any bad LEDs.

Closer look at the LED driver board finds a short on anode of 2 of 3 LED strings at on CN3 (pin 5 and 9) LED strings themselves have no shorts. Found a shorted MOSFET on each of the 2 failed boost converter circuit (Q21 Q24). These are 100V 15A MOSFETs in TO-252 package that basically use the ground plane as heat sink so they've lived a hard life. High res pics attached of before and after MOSFET removal (How did I ever fix things before hot air station haha)

Will order a LED driver board (same price as 2x MOSFETs haha) and report back the results.

[howardc64]

Re: vizio e650i-a2 backlight flashes then turns off

UPDATE

LED driver board came in. No short on the 3 boost converter circuit. Installed into TV, works.

Now onto the next problem in sequence. 4x wonky HDMI ports. All ports come and goes. Some times says no signal, some times say Not Support. Seems to change with each removal/reflow/install. Reflowed HDMI connector and switch (Parade PA421) pins. No shorts around the area.

This main board has 5 grounding fingers on bottom that requires the back case (very difficult to remove) on to secure ground path. Board doesn't have enough screws to keep the grounding fingers tightly against the chassis. When I had the back off and testing, just unplugging HDMI and move to another port would cause the first port to not work. Made more complex with the HDMI device getting confused and need to reset that...

Maybe HDMI switch is bad... maybe my reflow skills aren't good enough on fine pitch HDMI pins. don't know.

All other TV functions works fine. Tuning ATSC channels, running Vudu smart app, wifi so most of the board appears fine other than HDMI region.

[diif]

Re: vizio e650i-a2 backlight flashes then turns off

The BGA under the processor is more likely to be affected by heat than the HDMI switch.

[howardc64]

Re: vizio e650i-a2 backlight flashes then turns off

Seems doubtful its the main BGA. Here are some deterministic results.

SONY 4K bluray player works on HDMI 2/3/4
Xfinity flex (their streaming device) works on HDMI 2/4
Firestick 4K works on HDMI 2
Nothing works on HDMI 1

All devices display in 1080P which is max rez of the TV

I'd expect HDMI compatibility with SONY > Xfinity > Amazon. SONY is also the oldest device of this bunch and may play best with this circa 2012 HDMI implementation.

Anyway, enough HDMI is working for this old TV. I'll call it done

[diif]

Re: vizio e650i-a2 backlight flashes then turns off

Is HDMI 1 the bottom port? It looks like a couple of pins are bridged.

[howardc64]

Re: vizio e650i-a2 backlight flashes then turns off

Well here is one for the ages... Turns out I had 2 HDMI cables this TV didn't like haha

Cable 1 = Firestick 4K dongle short HDMI extender. I generally use this as firestick often can't be inserted into HDMI directly and its generally easier to insert with flexible short extender.
Cable 2 = Used on xfinity flex (typical length <= 2 meters)
Cable 3 = Used with SONY Bluray player (typical length, <= 2 meters)

TV didn't like cable 1+2. When I used cable 3, xfinity flex also worked on HDMI 1-4. And it turns out Cable 3 with bluray player worked with HDMI 1 as well.

I was able to barely get a contact with firestick without HDMI extender on HDMI 3 and it worked. Proving the TV didn't like the firestick's short extender. I do use this extender on many other TVs and it worked fine.

Wonder if all this has to do with the flimsy grounding design on the bottom of main board. Attached pic is not my board but there are only 2 screws that mounts the silver plate to the chassis. Rest of the ground depends on 5 springy fingers that aren't even soldered on. They depend on variety of plastic parts squeezing together to for the finger to make contact with the board and chassis ground. Including as I mentioned the difficult to remove rear plastic housing.

I first noticed all these problems when I hadn't fully assemble the back chassis for testing purpose. And the main board would just flop on those 2 screws on the silver metal piece. Slightest motion would kill the HDMI signal. I eventually taped it down and I suppose the TV still didn't like 2/3 HDMI cables I had.

[dskall]

Re: vizio e650i-a2 backlight flashes then turns off

May just have bad HDMI ports. So certain cables may work.

[nomoresonys]

Re: vizio e650i-a2 backlight flashes then turns off

something to try: Step 1: Turn the TV off.
Step 2: Press themenu button on the remote.
Step 3: Go to system —> reset —> factory reset.
Step 4: Enter the default code (-0000-)
Step 5: Select reset and then press ok.
Step 6: Wait for the TV to turn off and then back on.

[howardc64]

Re: vizio e650i-a2 backlight flashes then turns off

UPDATE:

Turns out was main board. Replaced and all 4 HDMI ports work perfectly with any HDMI cable.

[Lee M.]

Re: vizio e650i-a2 backlight flashes then turns off

Did the OP ever get this fixed? I have the same problem with a Vizio V755-j04. When I plug in the set the BL will flicker for 1/2 sec and then go out. U can see the Vizio logo with a flashlight. Check voltages on the connector from main board and they all look good. Pin 15 (BL on/off) shows 5V so BL should be on. Checking the two connectors going to the BL's I get .6V. Thinking maybe a shorted led is pulling down the voltage I removed the connectors and turned the set on again and get the same .6V. Question: Shouldn't I be seeing around 120V or so on the BL connector pins with the BL's disconnected if the driver board is good? thanks, Lee