Picked up a Sanyo DP37647 from a guy who said it just died while he was watching it. I determined there was a problem with the CPU after cooling it down with an inverted can of compressed air. As long as I kept the CPU cold the TV functioned normally.
I don't think the CPU can be replaced. A replacement board (N4PH) is a little less than $100 but there don't seem to be any available right now.
I managed to mount a small PC CPU fan at the bottom of the main board that draws air from the bottom of the TV and blows it up over the CPU. Unfortunately I didn't take any pics before putting the back cover on. I'll post something if I ever open it up again.
The fan cools things enough to use component video but not HDMI. I suspect HDMI puts greater demands on the processor and the fan doesn't provide enough cooling. HDMI does work when the CPU is iced-over from the inverted air can but that's not a practical way to watch TV. :)
One other thing, I took 12V from the power board then ran it through a 7805 to slow it down and keep the noise down. Don't know how long this fix is going to last but it's working great for now!
