Vizio E371VL starts to Vizio logo

[tibimakai]

I have picked up this TV knowing that is an EEPROM issue(first for me).
It's not the famous u18 one though. It's a different board.
On this board is us4 the chip.
I have purchased one on Ebay from shopjimmy, for $28 shipped.
Replaced it and it goes over the logo to a black screen with sound.
I have measured the 400V and it's not there, it's only 160V.
The other voltages are there at the connector. I'm not sure about the Status pin. What that is? It measures 3.03V.
The PWM IC is OZ9977BGN. I can't find dataheet for this IC.
It's safe to say that I need to replace it, since I can't check it?
It's located on the left side of the board at the bottom, it's the biggest there, 20 pin.

[tibimakai]

Re: Vizio E371VL starts to Vizio logo

Nobody can help?

[tom66]

Re: Vizio E371VL starts to Vizio logo

It never rises from 160V?
Blimey, that is an anaemic board for a 37".

[killian6pk]

Re: Vizio E371VL starts to Vizio logo

Have you tried reflowing those chips. That was one problem that seems to come up with the Vizio models similar to yours.

[tibimakai]

Re: Vizio E371VL starts to Vizio logo

I will have to monitor that voltage from when I start it up. I haven't done that yet.
I haven't tried re-flowing those chips yet. Would you know which should I try?

[tibimakai]

Re: Vizio E371VL starts to Vizio logo

No change at start up, it drops 3-4V and then goes back up to 161V-167V.
I'm wondering if this issue can be from EEPROM also or not?

[tibimakai]

Re: Vizio E371VL starts to Vizio logo

Found the problem, it was D602-MUR460, circled in the picture.
It was conducting both ways.
It's running now! It's a super light LCD TV.

[budm]

Re: Vizio E371VL starts to Vizio logo

That is PFC Diode, so that means the voltage on the main cap never goes up 370~390VDC.
Great job finding the cause of the problem. I always check the DC voltage on the main cap first to see if the PFC is working or not (if the circuit has PFC).

[tibimakai]

Re: Vizio E371VL starts to Vizio logo

I haven't checked that. I have seen that it's working and I didn't even think about checking that.
The main capacitor is a 450V one, so it should go to 390V.

[tom66]

Re: Vizio E371VL starts to Vizio logo

Only if it has PFC. TVs without PFC max voltage only ~input AC * 1.41.

[Leadguitarist1990]

Re: Vizio E371VL starts to Vizio logo

I am having a very similar issue with my e371vl. It starts up to the Vizio logo on the screen blinks once and then goes back to a black screen. I can still shut the tv off by pressing the power key on the tv. I've noticed by removing the rear cover that there is a little blue led light on the back of the power board. When the screen goes black after displaying the logo for a few seconds this little blue light fades away. I tried unplugging multiple ribbons and cables from both boards and checked all connections and I always get the same thing. I'm pretty handy with a multi meter and a soldering iron. I could just use a little guideance in my quest to fix this tv! I have searched hours on end through the inter webs and can't find anything that is exactly like what I'm experiencing!! Someone please help me! Thanks in advance!!