Vizio E390-A1... faulty PS or MB?

[VWAffe]

Hi all - have read the basic guides on troubleshooting and am hoping to get a second/third opinion before shelling out cash for a new MB or PS.

As the title says, the patient is a 14-month old Vizio E390-A1. One day not long after warranty expired, it would not power up via button or remote. This model doesn't have a standby led, but does have a small power led - presumably tied to the PS_On trigger. (It's not lighting up.)

More info:
- It has been left unplugged overnight+, then tried again. No joy.
- Checked voltages: when plugged in, the PS puts all nominal voltages. (Always on?) The 5V, 12V, and 24 V outputs are good on all pins.
- However, the PS_On trigger is always at 0V. No response from power button push or remote.
- Replaced the U409 EEPROM, as I've read this has been associated with such behavior. It was frankly the cheapest possible fix, but no joy. Took all anti-static precautions, and am pretty good at solder work.

My question(s) is(are):
- Is it normal for all the PS outputs to be powered all the time? Since there's no PS_On trigger, I originally suspected the MB, but based on what I've read in the various guides, the constant-on state of the PS doesn't seem right either.
- Not sure which part to replace next... no apparently bad caps/other parts on either based on close visual inspection.

Thoughts/suggestions welcome!

[audiofreak19]

Re: Vizio E390-A1... faulty PS or MB?

I would look into the power button circuit board. It's gotta be something with the main board or power button board cause the main board is what sends the signal and power to turn the led on.

[VWAffe]

Re: Vizio E390-A1... faulty PS or MB?

Thanks. I'm inclined to replace the main board.

Is it normal for the power supply to put out full voltage on the 12V and 24V branches when the TV isn't on? Some of what I've read leads me to believe that normal behavior is for only the 5V supply to be on all the time it's plugged in.

[audiofreak19]

Re: Vizio E390-A1... faulty PS or MB?

No it's not normal. It's basically saying that the second you plug the tv in there must be a short with the button allowing the voltage go through and turn on the tv. Try disconnecting the board that has the buttons on it and plug the tv in to see if you have those voltages.

[budm]

Re: Vizio E390-A1... faulty PS or MB?

Which version of the power supply board do you have?
http://www.shopjimmy.com/catalogsear.../?q=Vizio+E390

[VWAffe]

Re: Vizio E390-A1... faulty PS or MB?

Which version of the power supply board do you have?
http://www.shopjimmy.com/catalogsear.../?q=Vizio+E390

It's the ADTVCL801UXE4.

Hope to have some time tomorrow afternoon to open it up again.

Thanks to all for the advice so far.

[VWAffe]

Re: Vizio E390-A1... faulty PS or MB?

OK - based on more diagnosis, I think the MB is faulty:

- disconnected button board; same behavior (PS always on when plugged in, but no on/off signal, and no backlight control voltage from MB)
- disconnected IR receiver board; no change
- disconnected MB from PS... and voila - the PS only energizes the 5V standby supply when plugged in. Applying 5V to the PS_ON terminal energizes the 12V and 24V supplies. So, I deduce that there's a fault/short in the MB.

Am I missing anything? Thanks for the help!

[VWAffe]

Re: Vizio E390-A1... faulty PS or MB?

Have to clarify my original post: The PS_ON pin has always been energized at 4.2V when the MB is connected. The #1 "On/Off" pin is always at 0V.

[audiofreak19]

Re: Vizio E390-A1... faulty PS or MB?

I would say it is the main board. I had a Westinghouse that when pluged in it had all voltages just like yours. Mine ended up being a common cap that goes bad but doesn't bulge on the mainboard. So I would say its most likely the main board. Did you start testing any components on the mainboard.

[VWAffe]

Re: Vizio E390-A1... faulty PS or MB?

I would say it is the main board. I had a Westinghouse that when pluged in it had all voltages just like yours. Mine ended up being a common cap that goes bad but doesn't bulge on the mainboard. So I would say its most likely the main board. Did you start testing any components on the mainboard.

No, haven't looked at individual components on the main board yet... still have some learning to do where that's concerned. I may give it a shot before forking out dough for a known good board.

[audiofreak19]

Re: Vizio E390-A1... faulty PS or MB?

Check the regulators one could be shorted look on budm's signature there is a good thread on how to test them. I just realized I just got done fixing a e390vl I do t know if yours is a vl or not but on mine I'm pretty sure the ic processor went bad on mine. So I just bought a main board cause it was only 26 bucks and I had already swapped the EEPROM.

[VWAffe]

Re: Vizio E390-A1... faulty PS or MB?

Doing the most basic of tests (limited by equipment... only have a basic multimeter; no capacitance or ESR meter), have determined that the lone 6.3v cap on the main board is shorted. For now, I just went and ordered a new set of main board caps from Mouser for about $5.

Where did you find a main board for $26? Shopjimmy wants about $70 for mine (an E390-A1).

[audiofreak19]

Re: Vizio E390-A1... faulty PS or MB?

Ebay.

[VWAffe]

Re: Vizio E390-A1... faulty PS or MB?

Resolution, finally: Procured a known good main board for $48 via eBay, and TV is back up and running like nothing happened. I learned a lot, but tried the family's patience while the TV was "in the shop".

-Note: "Shorted" cap was not; committed the sin of testing it while still on the board. In the end a waste of time except for the learning, but was able to remove and replace the SMD cap without much incident using basic solder tools.

Thanks for all the help! Will definitely be on the lookout for future repair projects.

[RMSW]

Re: Vizio E390-A1... faulty PS or MB?

So just for clarification (and b/c I'm facing the same issue right now)...

1. You replaced the power supply unit first and still no changes

2. You replaced the main board and were up and running?

I just ordered and replaced the PSB. Still nothing, so I'm trying to decide if I should keep using the refund money vizio sent me and keep trying to fix this set.

Vizio E390i-A1