Vizio M502i-B1 won't turn on

[budm]

Re: Vizio M502i-B1 won't turn on

The output of the IR sensor is pulsing high frequency around 35~60KHz range (depends on IR system).

[dskall]

Re: Vizio M502i-B1 won't turn on

Need picture of connector

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

Here are pictures of both ends of connectir

[dskall]

Re: Vizio M502i-B1 won't turn on

That looks like WI-FI

[budm]

Re: Vizio M502i-B1 won't turn on

http://www.shopjimmy.com/catalogsear...Vizio+M502i-B1

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

does anyone have any suggestions for what I should be trying next?
Thank you

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

Here is a close up picture of the board I thought was the ir sensor board. I now believe it to be a wi Fi sensor. I did verify that the second black wire does indeed go to ground.(by continuity check on ohm meter). With the hold down tape off, I was able to obtain correct voltages as follows:
Pin 1: Black 1 wire - 3.29 volts
Pin 2: black wire - ground (0 volts)
Pin 3: green wire - 3.25 volts
Pin 4: white wire - 0 volts
Pin 5: red wire - 5.07 volts
However, voltages do not change as a result of pressing power button on remote

[dskall]

Re: Vizio M502i-B1 won't turn on

So you have checked with a flashlight and have no image on screen? You should have a connector running from main to led driver board with a pin for BL-ON. Have you checked that for voltage? You also have a connector that runs from your buttons to main. May say key1 or something on legend check those for varying voltage when you push buttons. Also your above picture looks like WI-FI unplug it and see if it works. For whatever unknown reason bad WI-FI can keep tv from coming on. Above board is for internet access and has nothing to do with remote or keys.

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

Reply to dskall: thank you for pointing out that I had the wrong device completely. I feel pretty stupid. I thought the wi fi board was the ir sensor. I have now located the correct ir sensor on the set.(bottom right side of tv). For starters:The set does not have any buttons on the side or front of the set. Only button, is the On/off button which doesn't do squat. I have disconnected the wifi connector and tried to turn on set (nothing changed). I also, disconnected ir sensor and tried to plug in set, again nothing turned on. Here is a picture of the connector for the ir sensor. The following are the voltages on the 8 pins of the ir sensor.When monitoring voltages off of ir sensor board, the only change is on the red wire. It goes from 3.69 to 3.36 volts when the remote control power button is depressed. For what it is worth, any button depressed on remote makes voltage change to 3.36 volts on red wire.All other voltages on the other wires do not change.
Pin 1: purple wire - 0 volt
Pin 2: brown wire - 5.08 v
Pin 3 : red wire- 3.69 volts (changes to 3.36 volts when remote power on)
Pin 4: orange wire- 3.26 volts
Pin 5: yellow wire - 3.31 volts
Pin 6: green wire - 3.31 volts
Pin 7: blue wire - 5.08 volts
Pin 8: black wire (ground) -0 volts
I am going to stand tv up and do flashlight test and report back. Also going to try and find the bl-on pin. So far, I haven't spotted any ledgend for key1 or bl-on anywhere.

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

I stood the set up and repeated the flash light test with several flashlights. There is no video whatsoever when the set Is plugged in. I searched high and low for any legends on cable connectors between main board and led driver board for "bl-on" pin identification. There are no identifications on the cable for at either end.
There is a ten pin connector between the led driver board and main board, but there are no legends on either board to identify the "Bl-on" pin. At this time, I have no boast voltage on led driver board, no video, no working on off switch, no audio, not even a "on lite" when the set is plugged in (only a miniature "led401" that has a blue and pink color emitting from it in the main circuit board when set is plugged in). I have Low voltages (19.6 volts) on 24 volt power supply and 11.5 volts on 12 volt power supply rail. Unless, anyone has a another suggestion, should I consider purchasing a main circuit board or Led driver board? I would appreciate any advice at this time. Thank you

[dskall]

Re: Vizio M502i-B1 won't turn on

On your cn9101 connector what does your on/off pin measure?

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

I measured the on/off pin on connector cn9101 it was 1.14 volts. The voltage at this pin does not change whether the on off button is depressed or the remote control power button is depressed.

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

Does anyone have any further suggestions/advice for me to try?

[budwich]

Re: Vizio M502i-B1 won't turn on

you might want to back up a bit... especially with amount of "misobservation / direction" as to what you have done / measured and on what board.

Further, as an aside, what is the history of the set / problem?

If I read your "results" correctly, the set thinks it has PS-ON... but it also has "dimming" set. Further, unplug the on-off button board. Get your meter and check what happens at the switch itself when the button is pressed... via resistance test on the contacts.

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

Budwich:here is a picture of the on/off circuit board. For starters,the voltage on the two wires from the main circuit to the on/off board is 2.85volts. When the on/off button was depressed, the vintage drops to .3 volts. When the board is disconnected, the resistance on the two pins goes from infinte resistance to 479 ohms when the button is depressed. I suspect the zenor diode is open. I also drew a schematic of the board which I will send next

[dskall]

Re: Vizio M502i-B1 won't turn on

Reread post 17. Need to find bl-on pin to see if it is giving command to the led board to turn on.

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

Here is a drawing of the on/off circuit board that I drew from taking point to point resistance readings off. The Zenor diode appears to be open. I was wondering if any one had a suggestion as to what the zenor diode voltage rating should be. The incoming voltage is 2.85 volts. What do you suggest zenor diode zdo321 should be? The other question is what had happened just before the set quit. We had experinced power outages in the area where the power went on and off seven times. After the the power was restored, we were watching the tv and it went completely off.

[dskall]

Re: Vizio M502i-B1 won't turn on

You can check it in diode test just like regular diode. You should get reading one way and . No short or open.

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

Rely to dekall: I could not identify which pin or wire is associated with bl-on. So, imfllowed budwich's advice and tried to focus on the on/off board. As I previously mentioned, the on/off button had no effect on turning the set on. I believe that zenor diode (zdo0231) is open on the on/off circuit board. I would like to substitute the zenor diode and try to see if this will turn the set on. So, can any one recommend the zenor diode value( perhaps 1.85 volts)

[Misterfixit]

Re: Vizio M502i-B1 won't turn on

Dskall: I did check it several times. I can absolutely tell you the diode shown as zdo0231 is open (infinite resistance in both directions using the diode setting in my digital vom). I suspect that with out the zenor diode operating, the supply voltage from the main circuit board, gets dragged down when the push button is depressed. However, I suspect with the zenor diode operating correctly, the voltage is allowed to stay above a certain value which feeds back to the main board. When the push button is depressed, it changes this voltage and the main board then senses this change and turns on the bl-on to the led driver board. I am only speculating on this because i don't have a schematic or a sense of how the on/off board actually works to turn on or off of the set. What zenor diode voltage would you suggest?