vizio VU42FHDTV10A .. no pic or sound

[budm]

Re: vizio VU42FHDTV10A .. no pic or sound

How about the whole board? Do you hear the relay click when PS_ON is applied?
It looks like IC801, IC802 are for the PFC, please get the numbers as printed on the top of the ICs.

[viziodad]

Re: vizio VU42FHDTV10A .. no pic or sound

What threw me is the original & replacement couldn't both be bad, so I looked at other areas, like the pson being too low, and the jimmy website told me it was probably the main board shutting down the ps board.
Anyway, the ics are:
IC802 .. 25923 DASD03..extremely difficult to read, and IC801 is almost unreadable.

[viziodad]

Re: vizio VU42FHDTV10A .. no pic or sound

The resolution on my phone is too poor for the entire board.
Yes, the relay clicks when plugged in, and when on button on tv is pressed.

[budm]

Re: vizio VU42FHDTV10A .. no pic or sound

Ps_on of 3.1V is more than enough to turn on the transistor. We need the pin out of the IC so we can check the voltage and the resistance of the ICs. Getting bad replacement board is not uncommon at all.

[viziodad]

Re: vizio VU42FHDTV10A .. no pic or sound

The chip on both supplies is unreadable..I guess I have no choice but to order another ps board.

[viziodad]

Re: vizio VU42FHDTV10A .. no pic or sound

hmm..
Quote from a similar thread:

Summary of the problem so far:

The standby 5v portion of the power supply is functioning correctly, and sending that voltage to the main controller board. The main controller board will respond to the remote / push-button, and send a signal of 3.166v to the PSON, but the main portion of the power supply will only turn on for a fraction of a second when PSON first goes high (I am thinking that the initial voltage pulse to PSON will be a bit higher than 3.166, this can be tested if needed). The main portion of the power supply will turn on for a fraction of a second, and correctly send out 12v and 24v. After a few seconds the 12v and 24v settle down to around 1v. (This is the voltage that is being sent across fuse 1)

Independently setting the PSON to high with a pair of AA batteries will result in the main portion of the power supply turning on. This sends out a steady 12v and 24v to their rails, where they will remain constant as long as the PSON is being independently driven. A faint sound is heard from the speakers when the main board is correctly receiving the 12v.

It would seem as though the PSON voltage supplied by the main board is not high enough to tell the power supply to turn on.

Should my next step be to trace out the PSON pin on the main board, and find out where it should be getting its voltage from?

[budm]

Re: vizio VU42FHDTV10A .. no pic or sound

The PS_ON is the steady state not pulse, so if the moan board is only the pulse, that will not keep the power supply on. You can easily verify using 2AA batteries to simulate PS_ON but you must cut the wire for the PS_ON that goes back to the main board. One thing I asked earlier is that if you do hear the relay turns on or not.

[viziodad]

Re: vizio VU42FHDTV10A .. no pic or sound

Yes, I stated above that it does click.
I took the ps board with nothing connected except the ac cord, and connected the 2 AA batteries to the PSON pin, and the relay clicked, but still no 24 or 12vdc..
I then jumpered the 5vdc standby with a 1k resistor, and got the same results.
I think I am now convinced (just trying to eliminate other possibilities) that they sent me a bad PS board, and you are correct.
I will order another, and let you know.
Thank you much.

[budm]

Re: vizio VU42FHDTV10A .. no pic or sound

Ok, I did not see the edited answer about the relay, sorry about that. I hope you can return that defective power supply. I use shopjimmy because it is easy to deal with when I have problem.

[viziodad]

Re: vizio VU42FHDTV10A .. no pic or sound

No problem..I got the replacement board from Jimmy, bench checked it to make sure the 12 & 24vdc were there. both good..
Installed board, tv came on and worked perfectly, for 2 days..
Then the picture flickered, and the tv shut off, except for the white Vizio logo.
No 12 or 24vdc again. ..
Since the tv worked for a couple of days, I think it's another bad ps board, and notified Jimmy's.