Vizio E500i-B1 Backlight

[0S1R1S]

Hello folks, I have a set here that I need some advice on.
It was brought to me with this story.
Big thunderstorm, lightning strike hit house next door, TV wouldn't work after that. The backlight is failed. It does not come on at all.
I have shined a flashlight on the display and see the No Signal text, so the panel is good and it's powering on.
I checked voltages on the power supply board going to the main board. All check out fine, aside from every 24V output, it is coming up as 15.5-16V.
Pictures are attached of the whole back opened up, the main & network boards, and the power board.
The power board part number is ADTVE3613XA6.

[CapLeaker]

Re: Vizio E500i-B1 Backlight

Check the voltage on the main filter cap (the two 450V caps on the PSU) with the tv on. If you only have 170V DC with the TV on, the PFC isn't working. Be careful, as you are in the primary section of the PSU. No boosted voltage, no 24V.

[0S1R1S]

Re: Vizio E500i-B1 Backlight

Check the voltage on the main filter cap (the two 450V caps on the PSU) with the tv on. If you only have 170V DC with the TV on, the PFC isn't working. Be careful, as you are in the primary section of the PSU. No boosted voltage, no 24V.

Would those be the block style capacitors? I see two coil filters with two block caps right near the power input, but they are stamped 275V. I assume that's what I should be checking, just wanted to make sure.
I powered up the set and tested voltage on those two block style 275V caps and had 0V on my meter. See attachment.

[budm]

Re: Vizio E500i-B1 Backlight

The main filter caps are the two long caps laying on its side on the bottom right next to the Yellow PFC inductor.
https://www.badcaps.net/forum/attach...7&d=1474481054

[0S1R1S]

Re: Vizio E500i-B1 Backlight

The main filter caps are the two long caps laying on its side on the bottom right next to the Yellow PFC inductor.
https://www.badcaps.net/forum/attach...7&d=1474481054

OH, duh! I didn't even think to look at those.
But isn't it odd that the block caps I did check show 0 VDC?

Both of the 450V caps are reading good. 390 and 392 VDC.

[budm]

Re: Vizio E500i-B1 Backlight

OH, duh! I didn't even think to look at those.
But isn't it odd that the block caps I did check show 0 VDC?

Both of the 450V caps are reading good. 390 and 392 VDC.

That cap you measured is for the AC LINE FILTER, it is connected across Line and Neutral of the incoming AC.

So the PFC Voltage booster is working, which means the PS-ON command signal from the main board OK.
Vizio ADTVE3613XA6 Power Supply Unit
http://www.shopjimmy.com/vizio-adtve...upply-unit.htm
Pictures provided by shopjimmy.
It is going to need to do mare in-depth board tracing to find out why the 24V output is not 24V.
How about the 12V output, what do you get? It should be low too since it is generated by the same power transformer that generates the 24VDC.

[0S1R1S]

Re: Vizio E500i-B1 Backlight

All voltages off the power board check out, aside from the 24V.
Both connectors have 24V rails and they are all reading 15.5V.
The 5V and 12V rails are just fine, showing 5VDC and ~12.2VDC.

Perhaps I'm looking at the wrong board, and the issue is with the turn on signal for the backlights via the main board?

[budm]

Re: Vizio E500i-B1 Backlight

The 12V and the 24V are generated by the same power transformer, so if the 24V is low, then I expect the 12V to be low too.
What happen to the 24V if you disconnect the LED backlights connector from the main board?

[0S1R1S]

Re: Vizio E500i-B1 Backlight

The 12V and the 24V are generated by the same power transformer, so if the 24V is low, then I expect the 12V to be low too.
What happen to the 24V if you disconnect the LED backlights connector from the main board?

The voltages remained the same.
~12.2V on the 12V pins.
15.5V on the 24V pins.

EDIT : And I tried disconnecting the LED connectors from the main board, and also disconnecting the power supply connector to feed those LEDs.

[budm]

Re: Vizio E500i-B1 Backlight

OK, need to do more tracing on the 24V section from the output winding all the way to the 24V pin on the connector CN9102.
Oh and how about the CN9102 (the one with RED and Black wires) on the power supply board not connected at all, do you still get about 15V instead of 24V?

[0S1R1S]

Re: Vizio E500i-B1 Backlight

OK, need to do more tracing on the 24V section from the output winding all the way to the 24V pin on the connector CN9102.
Oh and how about the CN9102 (the one with RED and Black wires) on the power supply board not connected at all, do you still get about 15V instead of 24V?

I have to have CN9101 plugged into the power board to the main board or I won't be able to power up the TV. So I tried that. Still the same, 15.5VDC on CN9102, all 4 connectors.

[budm]

Re: Vizio E500i-B1 Backlight

I have to have CN9101 plugged into the power board to the main board or I won't be able to power up the TV. So I tried that. Still the same, 15.5VDC on CN9102, all 4 connectors.

That is correct that you have to have the CN9101 connected to get the power to the main board, but the CN9102 is not needed to be plugged in because it is the 24V for the LED backlights circuit only, we need to find out if something in the LED backlights circuits are loading down the 24V or not that is why I want you to disconnect the CN9102 (24V).

[CapLeaker]

Re: Vizio E500i-B1 Backlight

Did you check the diodes that are responsible for the 24v rail? Is there any ripple on that rail?

[budm]

Re: Vizio E500i-B1 Backlight

24V rail rectifiers:
D9103, 9106; Check them out.
Lytics Caps (7) C9114, 9129, 9131, 9132, 9133, 9134, 9135.
SMD Ceramic Cap C9116.

[0S1R1S]

Re: Vizio E500i-B1 Backlight

24V rail rectifiers:
D9103, 9106; Check them out.
Lytics Caps (7) C9114, 9129, 9131, 9132, 9133, 9134, 9135.
SMD Ceramic Cap C9116.

Do I need to remove the diodes before checking to get a proper reading? I think I tried that already the other night and they weren't shorted.

C9131 - Reading is all over the place. From .033 to 7 nanofarads.
C9132 - Same thing. May have an issue with my meter


Having trouble getting a reading on the ceramic capacitor C9116 in circuit, so I removed it and measured it at 47 nanofarads.

Really all I had time to dig into tonight. Girlfriend getting angry I'm working on our anniversary. =/

[CapLeaker]

Re: Vizio E500i-B1 Backlight

Look at the trace... Those caps are in parallel to get more uF and lower esr.

[0S1R1S]

Re: Vizio E500i-B1 Backlight

Look at the trace... Those caps are in parallel to get more uF and lower esr.

I'm sorry, I'm still trying to learn this stuff. So, being in parallel, that will increase the capacitance, I understand that, but why would the measurements be jumping around when they were out of circuit? I failed to mention that I removed those two from the board before checking them. So, either they are reading oddly, or my meter is junk.
Also, what exactly is esr?

By the way, before I forget, I really very much appreciate all the help! This community is great and one day I hope to be able to give back with my gathered knowledge and help others.

[budm]

Re: Vizio E500i-B1 Backlight

So what do you get on the diode mode for the D9103, 9106?
Also should check the solder joints on those two Transformers T9101, 9102 legs.

[0S1R1S]

Re: Vizio E500i-B1 Backlight

So what do you get on the diode mode for the D9103, 9106?
Also should check the solder joints on those two Transformers T9101, 9102 legs.

In circuit, from outer leg to inner, my meter shows .460 V in diode mode.
Out of circuit, from outer leg to inner, my meter shows ~.115 V in diode mode.

Solder joints on T9101 and T9102 look perfectly fine.

[budm]

Re: Vizio E500i-B1 Backlight

In circuit, from outer leg to inner, my meter shows .460 V in diode mode.
Out of circuit, from outer leg to inner, my meter shows ~.115 V in diode mode.

Solder joints on T9101 and T9102 look perfectly fine.

I cannot see why you are seeing higher Vf when reading in the circuit. I t has to be something in that 24V rectifier/filter section since the 12V (Rectified by D9104, 9109) is fine.