Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

[hdguy]

Multimeter: neg probe to frame, red probe standby pins on the wiring harness that goes from the power supply to the main board, I get 0v. In fact, I get 0v across all of the pins.

Main system board fuse continuity check (it's fine)
Plugged in checked AC @ main fuse: 122.8.
Also: No status or indicator lights at all

... is it as cut & dry as: Dead Power Supply?

If yes:
option 1: buy 0500-0412-1010 (are there other boards as viable alternatives?)
option 2: fix power supply (where do I start????, no visible issues - very clean board (see pic)

If no, it is possibly something other than psu -
then please advise on next steps

[Ltank]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

On the output of the bridge rectifier is the main filter cap. It should read about 170 vdc across it. It is across the rectifier output. 120x1.414=169.68. When the PFC is working voltage across the the main filter cap should be about 385 vdc

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Try heating those two caps with hair dryer and then apply power and see if you will get Voltage at the connector.

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Ok - I'm pretty lost already, from all of the googe'ing & YouTubing, I think I am able to provide what you asked for.

vdc readings on the bridge rectifier (BD101):
+: 107.5
~: 0
~: 0
-: -59.5

The large cap (C608A) measured:
+: 107.2
-: -59.5

For fun, I did check vdc readings on the two other caps that were pointed out, for the hair dryer trick, and they were both the same: -59.2 on all pins (C104 & C105).

I also checked for continuity on FB601 & F601 (fuses, right?) and it passed.

Is this helping narrow anything down?
Is it time to do the hair dryer trick?

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Ok - I tried the "dryer on the caps method" mentioned above (let it heat for about 90 seconds) and it did not change any of the readings. I hope I did it long enough, but I've had bad luck with this in the past, which included an Xbox 360 and a heat gun, so I am a little gun shy...

Any other thoughts on how to get low voltage up to the pin harness?

[tibimakai]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

I would jump the power supply, with some resistors between the standby pin to power on and inverter on pins and disconnect the main harness going to the mainboard.
You should have backlight on and all the voltages.
I have a E371VL with bad mainboard, same symptoms.

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

To be specific, are you suggesting, wire the following pins together (see photo of the mainboard connector on the power supply):

• ON/OFF (either one) --> 5.1VSB (any one of them)
• ON/OFF (the other one) --> 12V (any one of them)

From there, apply power and confirm:

• Blacklights should work
• I've got 5.1v & 12v @ the connector

Also, are resistors needed on both of the above scenarios, and if so, how big ?
......Is this all right?

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

OK before doing any jumping the pins, you are not getting the 5.1VSTBY Voltage, right? So we need to fix that 5V STANDBY power supply section first, since heating the caps did not cause the power standby power supply to start up, then we now need to dig deep down to component level testing.

BTW:
"Ok - I'm pretty lost already, from all of the googe'ing & YouTubing, I think I am able to provide what you asked for.

vdc readings on the bridge rectifier (BD101):
+: 107.5
~: 0
~: 0
-: -59.5

The large cap (C608A) measured:
+: 107.2
-: -59.5"

Those readings are all wrong because you are chassis ground as the ground ref point, you have to use the negative leg of the main filter cap as the ground ref when measuring DC Voltage on the primary (DEADLY SIDE!) of the circuit.
So measure the DC Voltage again right at the two legs of the main filter cap.

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Ok, I'll try again:

The large cap (C608A) measured:
168.5 vdc

vdc readings on the bridge rectifier (BD101):
168.9 vdc

The reading was the same regardless if I used the (-) of the large cap or the bridge rectifier.

This is telling us something.. right?! by the way, thanks for your help so far!

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

The main DC is working, this main DC is used by the standby power supply to run.
So now we need to work in that section where the caps are.
http://www.shopjimmy.com/vizio-0500-...upply-unit.htm
I will have to download the pictures from SJ first so I can tell you what test points to look at next.

[tibimakai]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Sorry about that, I have missed that.

[cliff_hootarski]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Also, the "Primary (Hot)" side of the power supply is denoted by the solid black line.
All DC voltage measurements should be done with your Black lead (-) on the Negative
side of the large brown electrolytic capacitor (looks like a can laying on it's side).

"Secondary (Cold)" side of the power supply is everything on the other side of the solid black line.
Voltage measurements should be taken with the Black lead (-) on the chassis (ground).

All diode/resistance measurements should be done with power off and power plug
disconnected/unplugged.

As Budm said, The Primary/Hot side of the Power Supply has LEATHAL Voltages, use
caution!

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Thanks for explain which (-) I should use Cliff & thanks for all the help so far guys!

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

I will have to download the pictures from SJ first so I can tell you what test points to look at next.

Awesome! Thanks Budm! Please let me know which test points to hone in on and I'll provide those readings right away!

Thanks for all your help so far! -Tim

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

The main DC is working, this main DC is used by the standby power supply to run.
So now we need to work in that section where the caps are.

Can anyone tell me which caps I should be testing and the next steps to narrow down this problem?

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

I am sorry about follow through on your thread, the thread was not high lighted so I did not remember about it.
I will try again this evening.
Pictures provided by SHOPJIMMY.

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Excellent - I am looking forward to learning the next steps!

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

OK, check fuse F601? WHITE RECTANGULAR BOX close to the 450VDC large cap to see if it is OK first, if it is then:
you can test the power supply board by itself first without having other boards connected to it, you will be measuring the DC Voltages on the two legs of the cap C104, C105 which are in the hot DEADLY side of the circuit so care must be taken.
You will have to flip the board so you can easily work on the bottom side of the board, make sure not to touch anything or let the probes slip on you.
We also need the P/N of U101 SMPS IC so we can look up the spec sheet for it.
You should pug the board into GFCI outlet for safety.

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

I have checked F601 in the past and it passed continuity (see above post), but I just checked it again and it is failing. Now on that particular fuse my multimeter hovers up to ~1529 whereas on the other continuity points, it rolls back down to 0000.

For testing purposes should I just short it with a small wire?

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

You are not testing the fuse with the TV plugged in, right? It should show less than 1 Ohm right away because it is basically a piece of wire, do not use beep mode, use Ohm mode for testing.