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Vizio 42" model #: M420NV - HDMI

Discussion in 'Troubleshooting and Repair' started by seriocode, Jan 4, 2013.

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  1. seriocode

    seriocode

    3
    0
    Jan 4, 2013
    I purchased my TV 2 years ago and my warranty ran out 30days after purchase.

    Everything was working fine until late last year out of the blue, my HDMI connection 1 just lost signal. No reason at all.

    1 week later, my HDMI connection 2 went bad. My speakers followed shortly after.

    I figured I still have 2 other HDMI connections so, I'll be ok. Wrong. My HDMI connect 3 failed and I panicked.

    I ordered a replacement main board from ebay and swapped the boards out.
    It fixed both problems and has been working just fine since.

    Just last week though, the same issues starting happening. I've already lost my volume, HDMI 1 & 3, and I'm afraid I might lose another HDMI soon.

    I could swap it out again, OR, what I would like is some help in diagnosing the issue?

    Is the cause for this issue on my Main Board (i suspect, because its a video issue)?
    or is with my power supply?

    is as simple as just swapping out an IC chip somewhere?

    I just need help with this issue cause I don't want to spend more than what the TV is worth... and I'm coming close to it too.

    If you need more info please let me know. Thank you who ever the savior of my TV is.
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,448
    2,809
    Jan 21, 2010
    Well, you know the final fault is on the board you swapped out. However the new board failed soon after, so something outside that board must be contributing to that failure.

    To me, the most likely scenarios are that it is being caused by problems in your power supply, or problems in the device you attached to the HDMI ports.

    You also can't completely rule out an age related component failure on the boards themselves if they were manufactured near the same time. In this case I would be looking at electrolytic capacitors on that board (and probably throughout the rest of the set too.

    Did you keep the old boards, or did you discard them?
     
  3. seriocode

    seriocode

    3
    0
    Jan 4, 2013
    I did keep the old board. What can I do with it?

    I also suspected it might be the power supply end of things.

    Is there any way to diagnose what the root of the issue is?
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,448
    2,809
    Jan 21, 2010
    Measuring the voltage delivered to the boards is a good start.

    Images of the boards might be interesting. If it is a capacitor issue it *may* be visible (I'm not pinning any great hope on this). See if you can see any capacitors with domed tops or with stuff leaking from them.
     
  5. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,270
    Nov 28, 2011
    It's interesting that the ports on your new board failed in the order that you used them. This seems to imply a problem with the signal, or perhaps the cable. The inputs may be poorly protected against surges and spikes.

    So, what are you connecting to the HDMI ports? And has it always been the same thing from the time the problems first started? How is it powered? Is there anything unusual about the cable?
     
  6. seriocode

    seriocode

    3
    0
    Jan 4, 2013
    Steve,

    I do have a picture of the old board, but I have to get home to upload it. I'll do that later today if that helps my situation out some. I'll also get the part number.

    I only connect my cable box, Playstation 3, and Blue Ray player.

    What do you mean the same thing?
    The HDMIs go then the volume. The ports that actually fail have varied though. HDMI though is the first to go on both occasions. (*note* there have only been 2 occurrences of this issue)

    The TV is being powered like normal. I do have it connected to a multi surge protector (which I do suspect to be a huge culprit, not sure though)

    No, the cables are fine, no issues with those.

    Any other info that might help?

    FYI: I'm somewhat computer inclined, but not that much.
     
  7. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,270
    Nov 28, 2011
    By "the same thing" I meant was it always the same device plugged into the HDMI ports when they failed, but you've answered that - there are three different devices.

    The ports that have failed have varied, yes, but has any HDMI port ever failed when there was nothing plugged into it?

    Also, was it always the same device plugged into the HDMI ports that failed?

    The devices you plugged into the HDMI ports, were they powered from the same surge protector? Or from an unprotected supply point?

    Do you remember anything failing WHILE the set was running? Or has it always been a case of "it was working last time, but when I turned the set on now, it doesn't work"?

    Are the HDMI cables especially long?

    Have you googled something like "hdmi port failure vizio" to see whether this is a known issue?

    I'm just "probing" here; I don't think I can help much, sorry.
     
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