CurtPalme.com Home Theater Forum

**Curt Palme** · Posted: Mon Jun 11, 2012 2:31 pm Post subject:

I'll met Mac answer this one. My guess is still the controller board, but a bad LCD can also cause this. A bad Tcon board can also be a possibility, but they don't fail as often as the controller. Without module swapping, there's no real way to tell, just like with the laptops you work on.

Unless Mac can give you more ideas, you just have to ask yourself if you want to throw $100-125 at it for a chance at getting it to work a while longer.

Michale32086 · Joined: 11 Jun 2012 Posts: 4

macgyver655 · Joined: 22 Aug 2007 Posts: 7059

Curt pretty much has it correct. Someone with good schematic reading skills and testing ability can easily find these problems but many schematics are not available. Because the manufacturers don't want it fixed. They want you to go buy a new one.

They put in crap parts and then don't release all the schematics. Tell me that's not a conspiracy.....

So even if you find a good used main, which it probably is the problem, that main is probably ready to fail also. So if your just a board swapper then your at the mercy of the manufacturer.

Michale32086 · Joined: 11 Jun 2012 Posts: 4

windup · Joined: 26 Jun 2012 Posts: 5

Hello. I have a similar problem with my less than 2 year year old Vizio VF550M.

Model: VIZIO VF550M 55" 120HZ 1080P LCD HDTV
Purchased Nov 2009

Event:
June 2012: Had output from a computer through HDMI port 3 on the TV. All of a sudden the TV turned off and started making a lot of clicking noises. I shut off the computer and unplugged the TV. Trying to turn on the TV just made more clicking noises. Only issue prior to this was HDMI input 1 stopped working with the computer.

TV Behavior:
Side panel power button does nothing. The TV will turn on and off by remote only. The screen does not show anything; it is just black as if it were not on. The only indication the TV is on is the Vizio logo goes from orange when off to white when on. Again, the screen does not appear to work at all and the buttons on the TV do nothing. The only thing that you can do is make the Vizio logo turn white by pressing the on button on the remote. The logo also dims a bit in and out.

All inputs have been unplugged now to prevent damage to them. I have taken apart the TV and do not see any obviously blown fuses or bad components. There are several boards on the TV; one that has the side buttons and inputs like HDMI (I think this is the main board), the power board, and ones around the sides of the TV that I think are the inverter boards (i'm not familiar with TV parts).

I think it may be the mainboard since the HDMI 1 went out earlier, and now none of the side buttons work to power on the TV, etc.

I think this is the part I need:
http://www.vizparts.com/product_detail.php?pid=1878
http://www.shopjimmy.com/new-vizio-3655-0022-0150-main-unit.htm

Also, this may be totally off, but someone mentioned reflowing the main board. The connection I have with 'reflow' is a laptop I had that the screen stopped working; it turned out the video card had desoldered itself from the motherboard and needed reflowing. I literally baked the motherboard in the kitchen oven like this guy: http://www.youtube.com/watch?v=Vya1bOwvTEo, and it has worked perfect ever since. Would this work with the TV main board as well?

windup · Joined: 26 Jun 2012 Posts: 5

Anyone?

**Curt Palme** · Posted: Mon Jul 23, 2012 1:36 pm Post subject:

All you can do is try it. Let us know what happens.

windup · Joined: 26 Jun 2012 Posts: 5

macgyver655 · Joined: 22 Aug 2007 Posts: 7059

I'd say ship it to me but it would probably cost a fortune. Where are you located?

windup · Joined: 26 Jun 2012 Posts: 5

OK, so you guys aren't going to believe this, but my VF550M now works perfectly, except for all 5 HDMI connections will not work. The TV had broke mid June - only thing that worked was I could turn it on only using the remote (side buttons did not work), and only the Vizio light would turn white. Nothing else, just a black screen of death. I had taken it completely apart and I had baked the motherboard to attempt and reflow it. It was still apart all over the floor on Friday Aug 3. We had company coming for the weekend, so I wanted to clean it up. Just out of curiosity I started messing around with it, turning it on and off, listening for humming noises and feeling around for heat. In the middle of doing this, probably the 10th time I turned it on, after a minute or so, the backlight suddenly came on. I looked at the front of the screen and it was blue with the no input!!! I hooked in the cable and up popped the Olympics. I ran upstairs to tell my wife and she didn't believe it either. It has been working since. However, I still can't get HDMI to work properly. It popped up briefly while I was trying the computer to HDMI out, but only showed the win 7 loading screen and then went to no input. Any ideas?

macgyver655 · Joined: 22 Aug 2007 Posts: 7059

windup · Joined: 26 Jun 2012 Posts: 5

**Curt Palme** · Posted: Tue Aug 07, 2012 5:35 pm Post subject:

Most likely you have cracked solder joints under one of the main control chips on the controller board. Just a guess. The solder joints crack but can come back to life, just like the RRoD failure on an XBox 360. Tomorrow it may not turn on at all. Or the screen will be blue, or any one of many other issues that these units have. Not worth repairing, as a used controller board on eBay can fail tomorrow with the same or other issues.

THere's a few Vizio posts here about various sets. Search them out, and see that others have had similar issues as you. Rampant amongst Vizio sets it would seem.

macgyver655 · Joined: 22 Aug 2007 Posts: 7059

One or more of the HDMI chips may be shorted causing a draw on 1 or more voltage supply lines. Now these supplies can sometimes go through multiple regulators before it gets to the chips. The supply being drawn on may be bouncing up and down a little and this supply could originate on a line that also supplies startup of the main unit it self. The draw may have changed just enough for the tv to start this time. Or, the short condition may have went open, there by eliminating the draw on the main supply which is why it now functions but no HDMI. You would have to do some voltage probing to see if there are any lines running low or fluctuating. The fact that the HDMI's are not working is your first hint as to where to look, or start at the main supplies and check for anomalies.