Vizio E550VL Black Screen/PSU

[msrods]

Re: Vizio E550VL Black Screen/PSU

Went back and rechecked the voltages on CN201 and CN204 using the ground pins on both connecters and I do not have 18 VDC or 12VDC PS-ON is 2.85 and the 5 VDC is 5.03.

[msrods]

Re: Vizio E550VL Black Screen/PSU

I guess I am going to assume that the Power Board is bad since I can get no readings of 18 or 12 VDC.

[TheTesterMan]

Re: Vizio E550VL Black Screen/PSU

msrods, I am having the same issue with same model. After much research, I am not sure you are completely right in regards to the Power Board. If there is no PS ON, then the power board will not fire those voltages.. The problem could still be the main board. I will continue to make measurements and report back

[budm]

Re: Vizio E550VL Black Screen/PSU

Went back and rechecked the voltages on CN201 and CN204 using the ground pins on both connecters and I do not have 18 VDC or 12VDC PS-ON is 2.85 and the 5 VDC is 5.03.

OK, that makes more sense now that you do not have 12V, 18V,or 24V because they are generated by the same circuit.
You do have PS-ON (2.85VDC).
The question is, the Voltage on the main cap still drops down from >360V to 160V as reported in post 9 when PS-ON still present?
We need to have that Boosted Voltage for the 12/18/24VDC to run.

It goes to 397 then drops back to 169.

[newtothis]

Re: Vizio E550VL Black Screen/PSU

msrods, I am having the same issue with same model. After much research, I am not sure you are completely right in regards to the Power Board. If there is no PS ON, then the power board will not fire those voltages.. The problem could still be the main board. I will continue to make measurements and report back

Stated at top of page there is >2.5v on PS_ON so main is sending signal.

[TheTesterMan]

Re: Vizio E550VL Black Screen/PSU

Here is what mine is doing.
Standby
-> Main Cap 160v
Power button
-> PS-ON @ 3.1v for 500ms only ( checked with scope)
-> Main Cap 350v for 5secs, then drops to 160v
12, 18 and 24v are always 0

[newtothis]

Re: Vizio E550VL Black Screen/PSU

Here is what mine is doing.
Standby
-> Main Cap 160v
Power button
-> PS-ON @ 3.1v for 500ms only ( checked with scope)
-> Main Cap 350v for 5secs, then drops to 160v
12, 18 and 24v are always 0

Attempted to jump PS_ON with a resistor yet?

[TheTesterMan]

Re: Vizio E550VL Black Screen/PSU

Would this be a resistor from VCC(5v) to PS_ON to keep the line high ?
If so, should I just create a voltage divider res circuit to drop it to 3.3 V ?
Of can I just connect an external 3.3v power supply ?

[TheTesterMan]

Re: Vizio E550VL Black Screen/PSU

Additional note: I hear a very faint buzz originating from withing the PSU, may guess is the transformer. Only there while @ 160v standby, not @ 350v

I am still unsure if I have a bad PSU or main board. I checked all the main regulators and they all seem to be working.

[msrods]

Re: Vizio E550VL Black Screen/PSU

OK, that makes more sense now that you do not have 12V, 18V,or 24V because they are generated by the same circuit.
You do have PS-ON (2.85VDC).
The question is, the Voltage on the main cap still drops down from >360V to 160V as reported in post 9 when PS-ON still present?
We need to have that Boosted Voltage for the 12/18/24VDC to run.

It is @C801A 398V at PS-ON and drops to 167V in less than a second.

[TheTesterMan]

Re: Vizio E550VL Black Screen/PSU

Additional info related to my issue.

The Cap V of 350v lasts for about 5 secs which coincides with the Remote Pin voltage of 3.3. Both pulse for a total of 5secs, while the PS-ON is a 500ms pulse.

I then connected 3.3v ( using another source ) to the PS-ON pin and Cap V is 160v. I do the same with the Remote pin and the voltage shoots up to 350v as long as I leave that pin pulled high.

Is PS-ON simply an ignition pulse, while the Remote Pin holds the PSU at full voltage ?

Regardless, I am %95 sure that my issue is PSU related, so I will continue to troubleshoot the Power Supply board using an external PSU on the remote pin.

[budm]

Re: Vizio E550VL Black Screen/PSU

Remote pin?
i do not see any pin on the power supply labeled with 'REMOTE' on it.
http://assets.shopjimmy.com/media/ca...0790-top_1.jpg

[TheTesterMan]

Re: Vizio E550VL Black Screen/PSU

Apologies for not including my PSU power supply board #, 0500-0502-2020 for E552VLE.

I am now able to get voltages, not sure how I did it, but again they only last as long as the Remote Pin pulse of 5secs. However, all the lines 12, 18 and 24v ramp up very slowly.. So much so that the 24 does not even reach 24 by the time the 5sec remote pulse is gone.

Should I start a different thread ?

[budm]

Re: Vizio E550VL Black Screen/PSU

Yes, it is not the same board we are trying to repair. I suggest you start a new thread with correct Make, Model, and good clear pictures of the board so I and other people will not get confused.

[TheTesterMan]

Re: Vizio E550VL Black Screen/PSU

Sorry, was going by the TV model # and not the PSU.
Will start a new thread tomorrow, thx

[msrods]

Re: Vizio E550VL Black Screen/PSU

I got rid of the TV, decided to by new one.