I just saw this post (I'm a little behind in checking Usenet), so hopefully
this will help. I repaired my 32" Vizio (similar insides to yours, I
believe) which had a similar problem.
In my case, replacing the mainboard fixed the problem. It seems that voltage
reagulators on the mainboard are common points of failure. I took the easy
way out and just replaced the mainboard which contains all of the logic, the
tuner, and audio amp. I was also having audio problems, so this fixed
everything.
Here are 2 sources for parts:
http://vizparts.com/index.php
http://www.searspartsdirect.com/partsdirect/index.action?pop=flush
Get the part number from the sticker on the mainboard inside the TV. Note
that some part numbers have been updated. That was the case when I looked up
the mainboard part number for my TV. You can buy new or refurbished parts. I
chose to get a refurbished part from Sears Parts Direct. The board was $110
plus $20 for tax and shipping and I received it within a week.
The hardest thing about this repair was getting the back cover off. There
are about 25 screws on the back cover alone. Next, you need to remove a
metal RF noise shield that covers the mainboard. That's another 12 or so
screws. Once all of that is done, 5 cable connectors need to be
disconnected. Two of them have the smallest pitch between pins that I have
ever seen and they need to be very gently removed to prevent damage. I
sweated through that part.
After replacing the board and the back of the TV, I powered it up and waited
for what seemed like a very long time before a startup message appeared on
the screen. Apparently, when the boards are reconditioned, all settings are
'zeroed' out like a brand new TV.
So after removing and replacing what seemed like a zillion screws, and
spending $130, the TV is back to normal.
Hope this helps.
-Nick