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Why won't the screen on my Vizio VO37L television power on?

I am trying to revive a Vizio VO37L TV, and making very little progress. I have read through several threads with similar symptoms and suspect the solution is there somewhere, but I need help with some diagnostics. Here are the symptoms and the diagnosis I have tried thus far…..

• When the power cord is plugged in, the VIZIO light at the bottom of the frame turns bright amber, then fades for a few seconds to about half the brightness, and stays amber.

• The screen is totally black, no light at all, and pressing the power button has no effect on the screen or the VIZIO light…it stays amber. (I do not have the remote control)

• I visually checked all the capacitors on all three boards, and could see no evident damage. After reading several threads, I I learned to check voltages at various points and here is what I have determined so far….

• The Power Supply board shows 5v at the 5VSB pins on connector CN3. It does not show voltage at the 12v pins. Voltage is also missing at the 24v pins of connector CN4.

• Therefore, it would appear the Power Supply board is failing, however I learned it has to be triggered by the Main board to turn on the 12v and 24v power.

• So I jumpered a 5v pin on connector CN3 to the PSON pin on CN3, and then I get 12v and 24v power on the respective pins of CN3 and CN4. Unfortunately, I still get no light on the screen and the VIZIO light remains amber.

There are likely other voltages that could be checked to further isolate the problem…at least to determine which of the three boards may be failing, so any advice is appreciated.

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I know it's about a year later and I am having a similar issue. It's possible one of the voltage regulators on your power supply board has failed. I know some of these Vizios have crappy capacitors but they also have crappy power regulator chips. If the voltage on one of those fails, or dips too low, you can get problems like you experience. It's also possible one or more of the EPROMs have failed, too. If you are getting power, it's quite possible the problem lies with the Main board. Good luck finding a replacement one of those. I've been searching on-and-off for a year. YouTube has a decent video of a guy checking the power regulators on his power board, though, and he makes the replacement look easy if you are comfortable soldering.

Update (01/03/2016)


I recently found a Vizio E371VL mainboard on eBay. I decided to jump and purchase. The board arrived Saturday. I replaced old with new, and now have a fully functioning Vizio again.

The cables required some attention. The mainboard connectors have tiny little clips that escaped my initial inspection. I discovered using a very small flathead screwdriver and fingernail this clips pop back (like a car trunk) and allow these ribbon cables to slip out.

A $60 dollar board and 30 minutes of time and I have a 37" HDTV to connect an old XBox 360 to.

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