Vizio Symptoms and Possible Solutions

[budwich]

Re: Vizio Symptoms and Possible Solutions

well... I guess you were seeing things... :-).

I can only go by your observations and how accurate they are. The tests that I suggested presented different "stages" of "stimuli" to the vga circuit into the main board since that is what you indicated was "driving" a different response from the tv. I guess that may not be true IF I understand your recent "observation"... although I am not sure that I understand your "changed cable and nothing else"... but was it plugged into your computer at this point. Basically, vga cabling provides a "multitude of grounds" on various pins along with some voltage (5v) as part of "capability signalling" to help with "resolution setting". The tests / checks of "blank connector", cable but not connected to source / pc, and connected to source provide different types of "stimuli" to the main board which might tell you where to look depending on which stimuli causes a response... which appears now that isn't happening at all. Does the hdmi cable act the "same" as you originally posted?

[budm]

Re: Vizio Symptoms and Possible Solutions

U46 is HDMI IC.
U43 for VGA (guessing).
Please lookup the pin out of the regulator IC so you will know which one is pin 1,...., I.E U5.

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

I see U5 pinout is as pictured.

Normally, does the DIM #14 pin on the power supply vary according to the applied voltage as the back light intensity is increased or decreased thru the video setting? My reason for asking is if I hot wire the DIM pin with 5.37 vdc, will this stop adjustment of the BL and therefore burn them out more quickly?

According to my interpretation of the voltages I pictured in my last post, they seem to be functionally normal.......correct?

[budm]

Re: Vizio Symptoms and Possible Solutions

I see U5 pinout is as pictured.

Normally, does the DIM #14 pin on the power supply vary according to the applied voltage as the back light intensity is increased or decreased thru the video setting? My reason for asking is if I hot wire the DIM pin with 5.37 vdc, will this stop adjustment of the BL and therefore burn them out more quickly?

According to my interpretation of the voltages I pictured in my last post, they seem to be functionally normal.......correct?

1) Your Voltage reports do not match the pin correctly:
You have: I.E. U5
Pin 1 = 1.8V
Pin 2 = 0.56v
Pin 3 = 1.8V
Pin 4 = 3.25V
So based on your reading and with correct pinout of U5 regulator IC:
Pin 1 (Adj) = 0.56V
Pin 2/Tied to big Tab (Vout) = 1.8V
Pin 3 (Vin) = 3.25V
It is OK, it is just that you did not have report the pin out correctly.

2) The Backlights Dimming control: at this point you can get the backlights to come on by forcing it with the resistor and without the need of HDMI or VGA connected to the TV, correct? Do you get the image and all the functions of the TV are all OK?

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

@budm asked "2) The Backlights Dimming control: at this point you can get the backlights to come on by forcing it with the resistor and without the need of HDMI or VGA connected to the TV, correct? Do you get the image and all the functions of the TV are all OK?" answer is NO, see below

Forgive me for the pinout placement errors, the is why I tried to give their location as recorded in the attached diagram. I am sorry, you professionals should not have to decipher the newbie's documentation since you are doing such a HUGE service to all us idiots, without getting paid. Sides that, in order for you to help as many as possible, you are very kind to be patient.

Ok, on to the new stuff. I was about ready to buy a new main board (MB), and be done woth this. Then while testing the voltages on the back of the MB, I discovered that when I jumper the power supply (PS) pin 2 to pin 14 with a 100u resistor, and #14 wire between the PS and MB NOT connected, and push the power button, the BL come on and the TV audio channel is playing, but the video is NOT there. So I do the same thing (jumpered PS 2 to 14, 14 wire not connected at MB) WITH an active HDMI plugged into the only working HDMI port#1 and the TV channels /audio work fine.
Therefore I still cannot identify the problem board, either PS or MB. The MB wire 14 DOES NOT send the 3 vdc to the PS, nor does it have anything to do with producing video on the TV channels. When the 14 wire is not connected at the MB, the TV working properly with sound (due to being started with an active HDMI plugged at startup), video and BL, the PS pin voltages are:

pin 11= 2.96
pin 12 = 3.27
pin 13= 0
pin 14=3.01 (not connected to MB)

Additional voltage checks on the MB:
Component Pin C Pin B Pin E
Front side:
Q27 2.39 1.10 0.06
Q29 3.8 0 0
Q30 0.03 0.64 0

Back side:
Q18 3.46 0 0
Q41 3.47 0 0
U14 Pin 1-4 = 0 pin 5-8 = 3.35

Note: the trash pickup is tomorrow, I have to get a clue........

If I force the BL from the pin 11 (PSON), it will start the BL but not the video and it still will not play the tv channel video, unless I have an active HDMI or VGA plugged to start it. I have looked pretty close for component level and trace physical damage, it is time to start swapping caps?


Sides that, if I force the DIM on in the PS, there probably will not be any control over the BL intensity and it will burn out quickly?

Update:
If I unplug the #14 DIM wire connected at the MB, with nothing else modified, push the power button, the Vizio logo that is orange(standby), turns to White, the BLs come on, but the sound, audio and video remain off.
If I do the same with a active HDMI connected, all works as normal and I can adjust the brightness, even though the DIM wire is disconnected at the MB.

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

@budm, late answer to your earlier question about grounded regulator, please see attached D722 pic, is that component bad?


@budwich, thanks. I been seeking a solution from the VGA "stimuli" symptoms. So let me try to explain. lets just start with a completely assembled tv, that when plugged into 110vac, shows the Vizio orange logo lit. Then the power button is pushed, and the Vizio logo turns white and there is no backlights, sound or video. So I push the TV power button again and it goes back into standby since the Vizio logo on the frame turns back to orange.
Then I plug a vga cable attached to an active Windows computer laptop, push the TV power button and the laptop "dings", indicating that it has sensed the new TV display being attached. The Vizio logo turns white again indicating that the PS is turned on and the TV acts normal with audio, BLs and TV channel video, BUT the video from the VGA input port is NOT visible when I select the input source as "comp" (vga) input, as it only displays "searching for signal" then "no signal" on the TV screen.
The TV does the exact same thing when attached by HDMI#2.
The TV does the exact same thing when attaching by HDMI#1 EXCEPT that it will show video on BOTH the TV NTSC on the TV channels AND/OR the HDMI#1 source, as selected by the input button.....

Therefore, I started investigating as you advised for the VGA input stimuli, hoping to get direction. I tried simulating the monitor RGB channel loads with 3 resistors, as in the attached drawing, and with adding a VGA pin 10 to GND and nothing changes.....ie, push the power button, Vizio logo changes from orange to white, no BL nor video nor audio. Either way the U46 (HDMI IC) and U43 (VGA IC) ICs both run about 93 degrees F.

When I plug a standard male VGA plug, without any wires attached, in and power on, no changes during power on, no video,audio, or BL.

So, I began checking voltages at the some of the VGA pins, on the MB.
With the VGA (with active vga signal) plugged into the VGA port and having normal audio, video and sound:
pin 12=4.39
pin 15 = 4.40
pin#4=0
pin# 9=4.56
pin#14=0
pin#13=4.4

Then without the VGA plugged, but with the video, audio and BLs running, the VGA pins were:

pin 12=1.22
pin 15 = 1.08
pin#4=0
pin# 9=0.47
pin#14=0
pin#13=0

So, I do not have a clue, even how to hot wire this thing.......or what to check next. I would buy a MB if I was reasonably certain that would fix it. Certainly, a MB would mitigate the HDMI#2 and VGA not showing video, but would it fix the normal operation of the TV NTSC ?

Go any ideas in which way to proceed?

[budwich]

Re: Vizio Symptoms and Possible Solutions

hmmmm...

I am not an expert on vga connections outside of some frustrated "effort" with trying to get a samsung dlp to talk to a PC. :-( In my travels "there", I found that not all vga cables are "equal". First, some do not have all pins wired. So, some metering has to be done to check end to end to see exactly what is wired in the cable. Next, some pins are internally wired in the connector as opposed to using end-to-end wires... these usually deal with grounds. further related, some have "grounding" associated with the connector housing while others do not and use the terminating equipment to "complete grounding" in various forms to allow the signalling. Lastly, there is voltages applied by the orignating / source equipment to get information (start exchanges) about resolution capability.

The tests that I suggested... first a blank vga plug (you buy these to build a cable). This plug would have no pins connected so no grounds would be connected except for maybe in the equipment that it plugs into. Thus, if your backlights don't come on and basically the tv doesn't start in this configuration, that would indicate that the vga "jacket" in the tv is not making any kind of grounding connection thru the body of the "blank connector plug". Which I think is what you indicated although I think you may be not be thinking about a "blank connector" versus something not plugged into the vga connection on the tv... those are two different things.
Next, when you plug in a cable but not into a pc, it is possible that the makeup of the cable is providing a variety of grounds within its make up. You didn't appear to do this as you already had the cable connected to the pc. The tv "started up" and "worked" but wasn't able to display the pc. It is possible that depending on the resolution setting, the system wasn't able to "negotiate" a resolution or possibly even start the exchange.... it could be even that some form of "sync" signal (in vga land) was not available.

It would appear that you are missing some form of ~5v in your mother board that is preventing some detection circuits from functioning until that voltage finds its way there via an external source.

Further, because some of your hdmi stuff doesn't work also, would give more credence that ~5v has an issue as hdmi uses that voltage to read the "sink" (display) capability to setup the hdmi resolution (and other things). When you plug into the "non-working" hdmi ports, do you get any indication that the cable connection is there but no signal or no acknowledgement of a cable. Some tvs grey out ports that are not "valid" while others don't seem to followany convention (ie. show all ports whether they are connected or not)

Lastly, I only suggested these tests to maybe help focus where to look in the circuit to find a problem (ie. grounds versus voltages and associated componets). It would still appear that the main board is the problem and perhaps you don't need to do more than replace it.

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

@budwich. I see and comprehend all you are saying in that I am an old school computer hardware expert. And yes the VGA may not display because of the incapable resolution, but I doubt that b/c the HDMI#1 works at that same resolution. And yes I used a plain unwired male 15 pin vga connector b/c I have lots of that stuff around here....

Anyway I had hoped that it was a simple "user error" and that I was unaware of the Vizio idiosyncrasy of the firmware. I keep thinking that the previous owner's kids were using this as a gaming monitor and that Vizio somehow has a glitch in it that when it was last shut down as a monitor, either VGA or HDMI it got stuck in this mode and would not light up unless one of those was attached.........but I did reset it to the factory setting and erased the cache from the settings menu and that did not solve the issue. I am still waiting for the right person to tell me its something simple like this......too bad I cannot update the firmware thru the USB port.

I would like to find that missing 5vdc and fix it or hot wire it to work as normal, but since these are all over Craigslist for 45 -65 dollars, and they are know to be short term, it is just something for me to learn on.....thanks experts like you and budm I am learning a lot, but will never be as good as you all.......Generally I think this kind of blog site is a wonderful, unusual thing in this day and age, so congrats to the head honcho and I hope it continues for many more years. Ultimately I want to get into the computer section of this website and give back on the parts I do know.......:>

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

So, I get out my bag of mostly used capacitors, removed from boards before that hit the trash and using my capacitor restore, I grabbed a handful and a full 45% were BAD, but did not look bad physically!! Ouch, I got to start testing everyone.

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

Please help this blind squirrel find his nuts. I do not know, and am hunting what I perceive as an issue on my power supply board. I have, what I think is a high speed switching diode with the marking of A7 3, where the 3 is horizontally enumerated. If it is what I think it is, it could be in one of three internal configurations....see the first pic attached(the config on the right in the first pic is what I think it is?). The second pic is from earlier, identified on the board as D722, and is what I am talking about herein. The last pic is of the entore backside of the 0500-0407-1020 power supply, with the D722 in the lower left corner (placing it on the secondary side). What is this and is this EVER supposed to have ANY of its 3 contacts going straight to chassis ground?

[budm]

Re: Vizio Symptoms and Possible Solutions

1) I do not understand why you call that diode regulator and call one pin Voltage in.
If you trace out the connection you can see that one of the pin is connected to GND.
2) I do not understand as to why you are looking at the power supply board.
3) That is backlights inverter section, if it does not receive the BL-ON and Dim signals from the main board then the backlights will not come on, you can force on the backlights by using pull-up resistors to prove that the backlights circuit is OK.
4) You did already hot wire the Dim and get the backlights to come on, did you not?" from your post: "discovered that when I jumper the power supply (PS) pin 2 to pin 14 with a 100u resistor, and #14 wire between the PS and MB NOT connected, and push the power button, the BL come on and the TV audio channel is playing, but the video is NOT there."

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

Ok, I guess I got to let the D722 go. Both it and the D723 are the same designated component that must work in tandem somehow, unbeknownst to me to figure out, but together must switch on the high power transformers to provide high power to the LEDs and BL thru C743 (grounded to chassis) and C729 (not grounded). See red tracing. Red dots indicate ground to chassis at those points. So, I am guessing the command signals go into C729 and back out C743.


I was ready to declare the mainboard (MB) defective, until I unplugged the DIM wire at the MB and saw the DIM output of the power supply (PS) go to a normal 3.03 vdc. Therefore, I got side tracked by assuming the DIM signal did NOT emanate from the MB....and started looking for issues on the PS again.

Even when the DIM wire was NOT connected at the MB, I could still adjust the backlight (BL) levels using the remote. If I knew a little more, I might figure this to the component level. No joy, nothing fixed or determined.

[budm]

Re: Vizio Symptoms and Possible Solutions

Just think about it, you are able to get the Light source (CCFL backlights (your TV)) to come on but you still do not have image on the screen, the light source is there so you can easily see the image on the screen. Light source can be CCFL, EEFL, or LED.
So at this point you can have backlights but no pictures but you can have picture if you have the TV connected to active VGA or active HDMI which points the problem to the main board but the exact cause of the problem we do not know yet.

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

How do the experts in here clean the boards before component level checking? Can I soak them in an ultrasonic alcohol bath without damaging the components? I got some boards from a house full of heavy smokers that are sticky and got CAT HAIR stuck across some components!! OUCH MEOW!

[Unspun01]

Re: Vizio Symptoms and Possible Solutions

As others have suggested, Mainboard is likely the problem and Power Supply is likely not the problem.

Specifically you have a missing voltage (like 5V) or a missing ground that is being fulfilled by using a VGA cable or HDMI cable when the other end is connected to a video source.

Instead of using a laptop or computer which can have resolution or display handshake issues, can you use the HDMI output from a dedicated video source like a Blu-Ray or DVD player? It is much easier to sacrifice a $25 DVD player than risk damaging an expensive laptop or PC video card for such testing.

Connecting a bare VGA cable, or a bare HDMI cable has no effect, so it's unlikely a missing ground, and more likely that the PC or device connected with the VGA cable or HDMI cable is providing the missing 5V.

See attached diagram. In VGA, Pin 9 is 5V. In HDMI, Pin 18 is 5V.

1) Try measuring Pin 9 (VGA) and Pin 18 (HDMI) on the mainboard without any cables attached.

2) Try measuring the same pins with the HDMI cable attached to a video output device.

MEASURE CAREFULLY AND AWAY FROM CONGESTED CONNECTOR PINS. 5V and GND are adjacent on HDMI connector and can be shorted very easily if your probe slips.

My bet is that you are missing 5V somewhere.

It's even possible that you have a defective HDMI IC which allows one HDMI port to work, but not the other. Or possibly a 5V line that supplies the HDMI IC, etc.

[Unspun01]

Re: Vizio Symptoms and Possible Solutions

How do the experts in here clean the boards before component level checking? Can I soak them in an ultrasonic alcohol bath without damaging the components? I got some boards from a house full of heavy smokers that are sticky and got CAT HAIR stuck across some components!! OUCH MEOW!

WAY TOO FANCY. No need for ultrasonic, and no need to waste so much alcohol in an ultrasonic bath.

Just use warm water with good amount of dish soap (like Dawn or Palmolive)

An old toothbrush does wonders for liberating sticky gunk and grease or smoking residue.

Use hot water to thoroughly rinse all areas of the circuit board.

Be sure to completely dry the board before reconnecting any power. ESPECIALLY under large BGA ICs or complex components like connectors or TV TUNER...

Use a can of compressed air to blow out excessive moisture. Don't use 100psi of compressed air because you will be sure to damage something.

I often place the circuit board in front of a warm furnace air register or AC vent to ensure it is completely dry.

You can even place in an oven at VERY LOW temperature with the door open so you don't cook the thing.

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

As others have suggested, Mainboard is likely the problem and Power Supply is likely not the problem.

Specifically you have a missing voltage (like 5V) or a missing ground that is being fulfilled by using a VGA cable or HDMI cable when the other end is connected to a video source.

Instead of using a laptop or computer which can have resolution or display handshake issues, can you use the HDMI output from a dedicated video source like a Blu-Ray or DVD player? It is much easier to sacrifice a $25 DVD player than risk damaging an expensive laptop or PC video card for such testing.

Connecting a bare VGA cable, or a bare HDMI cable has no effect, so it's unlikely a missing ground, and more likely that the PC or device connected with the VGA cable or HDMI cable is providing the missing 5V.

See attached diagram. In VGA, Pin 9 is 5V. In HDMI, Pin 18 is 5V.

1) Try measuring Pin 9 (VGA) and Pin 18 (HDMI) on the mainboard without any cables attached.

2) Try measuring the same pins with the HDMI cable attached to a video output device.

MEASURE CAREFULLY AND AWAY FROM CONGESTED CONNECTOR PINS. 5V and GND are adjacent on HDMI connector and can be shorted very easily if your probe slips.

My bet is that you are missing 5V somewhere.

It's even possible that you have a defective HDMI IC which allows one HDMI port to work, but not the other. Or possibly a 5V line that supplies the HDMI IC, etc.

Thanks Unspun01,
You got me thinking again and back tracking.
,
I have previously, partially done as you advised and got:
So, I began checking voltages at the some of the VGA pins, on the MB.
With the VGA (with active vga signal) plugged into the VGA port and having normal audio, video and sound:
pin 12=4.39
pin 15 = 4.40
pin#4=0
pin# 9=4.56
pin#14=0
pin#13=4.4

Then without the VGA plugged, but with the video, audio and BLs running, the VGA pins were:

pin 12=1.22
pin 15 = 1.08
pin#4=0
pin# 9=0.47
pin#14=0
pin#13=0

The above only told me that the VGA pin 9 was supplying the 5v, and that is what is coming from the computer plugged vga cable.

So I guessed I need to chase the VGA 9 pin trace and check the components there on, but I failed to find the culprit. The MB is hard to trace (unlike the PS), and I have not found a schematic for this MB.

I guess the failed component is a gate of some kind with a hi - lo signal.

[Unspun01]

Re: Vizio Symptoms and Possible Solutions

Captain:

Can you repeat the 5V measurement with HDMI 1 or HDMI 2 as the active video connection?

I don't know, but the 5V may be common to all 3 inputs, and if missing from all 3, you may find the culprit.

[Unspun01]

Re: Vizio Symptoms and Possible Solutions

Captain:

Check the shopjimmy link below:

https://www.shopjimmy.com/vizio-3637...for-e371vl.htm

There are 2 symptoms this kit fixes, and one sounds very similar to yours. The kit contains U18 and U21.

Depending on your symptoms, you may only need to replace one of the ICs.

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

Captain:

Check the shopjimmy link below:

https://www.shopjimmy.com/vizio-3637...for-e371vl.htm

There are 2 symptoms this kit fixes, and one sounds very similar to yours. The kit contains U18 and U21.

Depending on your symptoms, you may only need to replace one of the ICs.

Unspun01, yes the jimmy kit sounds like it MIGHT address my issue, but the same kit from others say the U18 and U21 kit will fix, quote:
"These main boards can have multiple failures, in addition to the EEPROM.
If EEPROM replacement does not repair your board, there are likely additional problems.
Symptoms EEPROM (U18) and U21 IC replacement kit CAN fix:
- Display is frozen on VIZIO logo screen*NOT My ISSUE
- TV won't power on with remote/buttons when plugged-in (VIZIO is lit in orange, but won't turn to white)NOT My ISSUE, mine turns white
- TV turns on when first plugged-in, but it won't turn back on after 30 minutes of being off NOT My ISSUE
- TV shuts off and goes back to standby mode (orange VIZIO lit) after you turn it on NOT My ISSUE
Symptoms EEPROM replacement CAN NOT Fix:
- TV turns on but has NO backlight IS My ISSUE if HDMI or VGA is NOT plugged and active
- TV turns on AND backlights are on, but has no video display at all IS My ISSUE, IF using and active VGA or HDMI PORT 2 at power on.
My BL never come on unless I have an active VGA/HDMI 1 or HDMI 2 device plugged when powered on
- HDMI issues"IS My ISSUE on HDMI port 2

I suspected the U21 early on but after testing, it is probably not the problem, but is the result of my issue being caused by switching hi / lo signals to it.

What you think? The statement "CANNOT fix HDMI issues" tells me there is likely additional issues.