Vizio M492i-B2 Won't Turn On

[CapLeaker]

Re: Vizio M492i-B2 Won't Turn On

We have to find the BLon signal in order to rule out the main board. Other than that, if the BLon is present, I would look hard on that those LED control IC's.
The BLon would act the same as PSon. Look for a DC voltage that appears when the TV is turned on and disappears when the TV is off.

[John90]

Re: Vizio M492i-B2 Won't Turn On

Took a break from the TV over the weekend. Still working on finding the BL-ON. I will let you guys know as soon as I find something.

[John90]

Re: Vizio M492i-B2 Won't Turn On

CapLeaker, if my BL-ON is present what do I need to look for on the LED control IC's? Having trouble finding BL-ON so I'm hoping I can work backwards from the LED control IC's.

[budm]

Re: Vizio M492i-B2 Won't Turn On

CapLeaker, if my BL-ON is present what do I need to look for on the LED control IC's? Having trouble finding BL-ON so I'm hoping I can work backwards from the LED control IC's.

Per post 17, we need the P/N of the ICs to look up the spec sheets.

[CapLeaker]

Re: Vizio M492i-B2 Won't Turn On

As budm mentioned, we need the part numbers of the IC's. Then go for the obvious like does the IC get proper VCC power. After that, its maybe see if we can disable the protection then switch out the IC's or get a new board.

But first we go there, we really need to figure out if the main is sending BLon, other than that, we will be troubleshooting all day long for nothing on the wrong board.

[John90]

Re: Vizio M492i-B2 Won't Turn On

Sorry about that. This is what I see on them.
U900/904-44DE S29B

U902/903-AS3820E E 1414XBH

[John90]

Re: Vizio M492i-B2 Won't Turn On

Guys, I have checked every pin on CN1, CN30, and CN901 and I do not see anything that goes from 0V to 3V when I try to turn on the TV. I thought maybe I was just missing it or something since nothing is labeled but I checked again and get nothing.

[CapLeaker]

Re: Vizio M492i-B2 Won't Turn On

That doesn't look good. The AS3820 is the LED control IC.
You say U900 and U902? At SJ I see U902 and U903 on the LED driver board?

At this point I'd say replace the LED driver board and see what happens. We know for some reason one side measures different from the other, which shouldn't be.

[John90]

Re: Vizio M492i-B2 Won't Turn On

I believe Budm asked about U900 and 904 as well but 902 and 903 are the AS3820's. ShopJimmy has a LED board for ~$18 so I will order one and hopefully that will fix the problem. If not, then problem is probably the main board?

[budm]

Re: Vizio M492i-B2 Won't Turn On

I would take a chance on $18 Dollars.

[John90]

Re: Vizio M492i-B2 Won't Turn On

Ordered! I will let you guys know what happens when I get it.

[John90]

Re: Vizio M492i-B2 Won't Turn On

Well guys, I have some bad news. Got the LED driver board in and hooked it up and still have nothing. Nothing happens when I try to turn on the TV. What should I do next?

[budm]

Re: Vizio M492i-B2 Won't Turn On

The 24VDC was on R9008 and 9010.
The voltage I am getting on capacitors TC903 and TC901 is
TC901=8.84VDC
TC903=12.54VDC

Still have the same Voltage reading as the old board?

[John90]

Re: Vizio M492i-B2 Won't Turn On

Just checked and I have the same readings on TC901 and TC903.

[budm]

Re: Vizio M492i-B2 Won't Turn On

This is not going to be easy at all since none of the connectors for that board is labeled.

[CapLeaker]

Re: Vizio M492i-B2 Won't Turn On

Well guys, I have some bad news. Got the LED driver board in and hooked it up and still have nothing. Nothing happens when I try to turn on the TV. What should I do next?

That's not good. you can do a full board swap out. It's $75, which would be the next easiest thing.

Hard to do anything on that set without knowing what the pins do. At this point I would say that the main board isn't sending BLon.

[John90]

Re: Vizio M492i-B2 Won't Turn On

Should I just buy the main board? Found one on ebay for $30.

[CapLeaker]

Re: Vizio M492i-B2 Won't Turn On

That is preference, I guess... but 75$ for all the boards from a trusted seller is a better deal to me... not that you are going to need something else later... The TV should be worth a 100 bux... since it is a fairly recent model.

[John90]

Re: Vizio M492i-B2 Won't Turn On

Update!

The good new is, I ordered a main board and it just came in. I installed the new board and now the TV turns on! Finally!

Bad news....looks like the display is cracked

[budm]

Re: Vizio M492i-B2 Won't Turn On

Oh man! you just cannot win on this one.