Vizio E420VA 5v drops to 3v when power cable is connected

[SeaglassPearl]

Folks, I have a Vizio flat screen that doesn't show any signs of life (and no orange vizio glow either).

I tested the voltages from the power board (at the connector) and I can see the 5V supply drops to 3V after the power cable is connected to the main board (5V supply reads as 5V when cable is disconnected from main board). All other rails (12V and 24V) are reading fine.

I looked for the usual bloated caps and saw none on either board and no other tell-tall signs (black marks, burned components, etc) on either side of both boards.

Given the 5V rail drops to 3V when the boards are connected via the cable is obviously a bad sign but I cannot tell which side of the fence the issue lies. Any hints to further diagnose or any other clues?

Happy 2023!

[nomoresonys]

Re: Vizio E420VA 5v drops to 3v when power cable is connected

maybe heat up that area of the mainboard with a hairdryer, heat that area with those looks like maybe 5 electrolytic capacitors by the connector for a couple minutes, then see if the 5 volt holds longer, don't wait til it cools off, test it while its still hot.

[diif]

Re: Vizio E420VA 5v drops to 3v when power cable is connected

Measure the resistance on the 5v line.
Use the Go Advanced button below and the paperclip to add photos.

[SeaglassPearl]

Re: Vizio E420VA 5v drops to 3v when power cable is connected

Went to try your insights, unfortunately one of the kids had stepped on the loose MLB in the garage and it's cracked :-(

Appreciate the tips.