Vizio VO320E Bad Power Supply Board

[craftech]

Vizio LCD TV Model VO320E
Power Surge in house occurred with unit turned off and plugged in. No picture or sound. No lights.

Power Board DPS-172EP A (0500-0407-0730)

Read the following thread which was helpful:
https://www.badcaps.net/forum/showth...+vo320e&page=2

Fuse is good

Checked this large electrolytic cap's voltage in standby = 154 volts
https://www.badcaps.net/forum/attach...0&d=1376775470

Bottom of Board:
https://www.badcaps.net/forum/attach...4&d=1376780218

Checked the diodes with board removed. All seemed good. Voltage one way only.

Output on the three 5V pins is good
But NOTHING any of the three 12V pins. No voltage.

Anyone know what to check to fix the board?
Only used boards are available currently.

Thanks for the help.

Regards,

John

[budm]

Re: Vizio VO320E Bad Power Supply Board

What DC voltage do you have at the PS_ON pin?
This is your board?
http://assets.shopjimmy.com/media/ca...7-0730-TOP.jpg

[craftech]

Re: Vizio VO320E Bad Power Supply Board

What DC voltage do you have at the PS_ON pin?
This is your board?
http://assets.shopjimmy.com/media/ca...7-0730-TOP.jpg

Thanks for responding to my question so fast Bud. I truly appreciate that.

Yes, that is my board.

When I put the multimeter negative lead on one of the ground pins and test the hot pins with the positive lead I get the following:

Around 5 volts on the three +5V pins
A reading of - 0 on the three 12V pins
A reading of - 0 on the PS_ON pin.

Regards,

John

[budm]

Re: Vizio VO320E Bad Power Supply Board

OK, the main board is not sending the ON signal to turn on the main power supply, when you activate the power switch, the PWON should go from 0V to >2VDC.
You should check the fuses and the voltage regulators on the main board next.
See LDO testing on the link below and report the voltage readings in the proper format.

[craftech]

Re: Vizio VO320E Bad Power Supply Board

OK, the main board is not sending the ON signal to turn on the main power supply, when you activate the power switch, the PWON should go from 0V to >2VDC.
You should check the fuses and the voltage regulators on the main board next.
See LDO testing on the link below and report the voltage readings in the proper format.

Got it. Will do.

Thanks,

John

[craftech]

Re: Vizio VO320E Bad Power Supply Board

I wanted to post a picture of the Mainboard for reference:

Part Number 071-2271-2846

http://www.retechtv.com/products/363...dJ9OgodJnQAzw#

John

[budm]

Re: Vizio VO320E Bad Power Supply Board

http://assets.shopjimmy.com/media/ca...3208420150.jpg

[craftech]

Re: Vizio VO320E Bad Power Supply Board

http://assets.shopjimmy.com/media/ca...3208420150.jpg

Fantastic picture. Thanks Bud.

I watched this YouTube video and tested the main board.
http://www.youtube.com/watch?v=cNFzBJELFoU

1. Tested the two gold tipped fuses. 5V both sides on one. 0v both sides on the other. Unit doesn't power on so I couldn't test for 12V each side on the second fuse. Seems like they both are working though.
2. Tested the Voltage Regulators.
3. U11 is a 7805. No voltage on input or output pin
4. U4 is a 1117. Input 5v, Tab and Center Pin 3.27v, Adj. pin 2.03v
5. U9 is a 1117. Input 4.93v, Tab & Center Pin 2.48v, Adj pin 1.24v
6. U8 is a 1117. Input 3.23v, Tab and Center pin 1.23v, Adj. pin 0v
7. U2 is a 1117. Input 4.92v, Tab & Center pin 3.27v, Adj. pin 2.03v
8. U5 is a 1117. Input 4.93v, Tab & Center pin 2.60v, Adj. pin 1.36v
9. TUS2 is an EH13A. Input 0.33v, Tab & Center pin 0v, Adj. pin 0v
10. U24 is a G1084 that has 2 pins connected with the center pin not connected (marked VO). Don't know what to do with that one. Wasn't in the YouTube video.

Regards,

John

[budm]

Re: Vizio VO320E Bad Power Supply Board

3. U11 is a 7805. No voltage on input or output pin: This one is fed by the 12v power supply, so it will not show voltage reading due to 12v is not turn on yet.

4. U4 is a 1117. Input 5v, Tab and Center Pin 3.27v, Adj. pin 2.03v: 1.25 + 2.03 = 3.28V out, OK.

5. U9 is a 1117. Input 4.93v, Tab & Center Pin 2.48v, Adj pin 1.24v: 1.25 + 1.24 = 2.49V, OK.

6. U8 is a 1117. Input 3.23v, Tab and Center pin 1.23v, Adj. pin 0v: This may be 1.25V fixed V reg, OK.

7. U2 is a 1117. Input 4.92v, Tab & Center pin 3.27v, Adj. pin 2.03v: 1.25 + 2.03 = 3.28V, OK.

8. U5 is a 1117. Input 4.93v, Tab & Center pin 2.60v, Adj. pin 1.36v: 1.25 + 1.36 = 2.61V, OK.

So, you do not see the ps_on changes state at all?
Shopjimmy sells EEPROM for this model, it can be bad EEPROM problem but I do not know how you can verify it.

[craftech]

Re: Vizio VO320E Bad Power Supply Board

So, you do not see the ps_on changes state at all?
Shopjimmy sells EEPROM for this model, it can be bad EEPROM problem but I do not know how you can verify it.

Bud,
Thanks for the detailed response.
Maybe I am not sure how to check the ps_on. Is there a way to trigger it to test it?
It seems to me that the power surge with the TV off would fry something else besides the EEPROM wouldn't it?

There are no lights on the set, nothing.
John

[budm]

Re: Vizio VO320E Bad Power Supply Board

You can force on the power supply by disconnecting the cbale between the power supply and the main board, then use 500~1K resistor between 5vstby and the PS_ON pin to force on the power supply, you should see the 12v OUTPUT.

[craftech]

Re: Vizio VO320E Bad Power Supply Board

You can force on the power supply by disconnecting the cbale between the power supply and the main board, then use 500~1K resistor between 5vstby and the PS_ON pin to force on the power supply, you should see the 12v OUTPUT.

That worked like a charm Bud. I cannot believe how much fun this is and how much I am learning. I can't thank you enough for teaching me.

Got 12v on all three pins with a 1K jumper resistor. So then I assume that it is the 5v pins on the P/S that power the circuit(s) on the Main Board that supply 3.1v back to the PS_ON pin on the P/S.

So 5v is getting over to the Mainboard OK, but the Mainboard is not generating the 3.1v when you press the Power Button that turns on the 12v section of the P/S.

ShopJimmy says EEPROM is U18, but I am not finding it on the board:

http://www.shopjimmy.com/vizio-vo320...eprom-only.htm

Regards,

John

[budm]

Re: Vizio VO320E Bad Power Supply Board

You can contact SJ and ask him the question about the EEPROM, he is very helpful about it.

[craftech]

Re: Vizio VO320E Bad Power Supply Board

You can contact SJ and ask him the question about the EEPROM, he is very helpful about it.

OK Bud,

Will do. Will post back results.

Thanks again,

John

EDIT: Left a message to call me back. Meanwhile I found the U18 EEPROM. It's on the bottom of the Main Board.

[craftech]

Re: Vizio VO320E Bad Power Supply Board

Follow-up

I spoke to someone in the tech dept at Shop Jimmy.

They didn't think it was the EEPROM because there aren't any lights at all. [Not even the logo is on]. [Correction: See my next post] He thinks the entire set is fried and that I should junk it.

Not good news, but they saved me a lot of money replacing power supply, mainboard, and possibly the LCD panel as well. He thinks that the power surge may not have necessarily been through the AC input. It may have come through the coaxial input as well.

But I learned an awful lot about LCD TV testing from you Bud and for that I am truly grateful.

Regards,

John

[tom66]

Re: Vizio VO320E Bad Power Supply Board

I think you would be a little hasty to throw away this set.

We've only ever seen power supplies and main boards damaged by power surges - the LCD panel survives.

If the EEPROM is a no go, I would replace the main board.

At the very least, chuck it on craigslist for $30 and it will be gone in a day... better than throwing it out and letting it rot.

[craftech]

Re: Vizio VO320E Bad Power Supply Board

I think you would be a little hasty to throw away this set.

We've only ever seen power supplies and main boards damaged by power surges - the LCD panel survives.

If the EEPROM is a no go, I would replace the main board.

At the very least, chuck it on craigslist for $30 and it will be gone in a day... better than throwing it out and letting it rot.

OK, my old man eyesight will be the death of me yet. The Vizio logo IS in fact lit up.

All this time I had the panel laying on it's face and was lifting it up to look at the front and didn't see the logo lit up.

I just stood it up on edge and plugged it in and there it was, lit up in yellow.

Now I feel like a fool calling them back. So embarrassing.

John

[craftech]

Re: Vizio VO320E Bad Power Supply Board

Hello Tom and Bud,

I was wondering if either of you think I should just go ahead and order that U18 EEPROM on the bottom of the Main Board anyway? The part number is very hard to make out, but it looks like MX (Macronix International) 25L32 (50i or 5Di?) Can't find that part number especially the last part. Pix on Shop Jimmy doesn't show a part number at all. $25 non-returnable even if it is the wrong part.

Regards,

John

[johnboy1313]

Re: Vizio VO320E Bad Power Supply Board

John, I've been following this post and it just clicked in my head that I have this set in my basement with a busted screen. The screen is so severely smashed that I never even attempted to plug it in, but I can get you part numbers if you want. I can't say for sure that the main board works, but I may be able to disconnect the panel from the T-Con, connect a source, and see if I get sound. I know it doesn't prove anything, but it would at least suggest that the main board and power boards are working. Though now that I think about it, as bad as the screen is, I wouldn't be surprised if a bulb or many bulbs are broken too. It may not power up at all. I'll let you know if I have the same main board when I get home in about 5 and a half hours. Where are you located?

[craftech]

Re: Vizio VO320E Bad Power Supply Board

John, I've been following this post and it just clicked in my head that I have this set in my basement with a busted screen. The screen is so severely smashed that I never even attempted to plug it in, but I can get you part numbers if you want. I can't say for sure that the main board works, but I may be able to disconnect the panel from the T-Con, connect a source, and see if I get sound. I know it doesn't prove anything, but it would at least suggest that the main board and power boards are working. Though now that I think about it, as bad as the screen is, I wouldn't be surprised if a bulb or many bulbs are broken too. It may not power up at all. I'll let you know if I have the same main board when I get home in about 5 and a half hours. Where are you located?

Thanks a lot John. That's wonderful news.

I am in Upstate, New York

Regards,

John