Sanyo Vizon 42" DP42647 TV turns on, shows input mode for about a second then goes black,

I think it is more than a Kool-Aid stain. likely it was some kind of heat applied to the screen causing physical damage. How does it appear when the screen is white?

It sounds that the main digital board to this TV is faulty. Contact any service technician.

have you checked it on video inputs on rear of set and also on tuner inputs to see if problem on all inputs?

Some food for thought here the power supply and part of the set:

I see so many here with no sound/nopicture issues:

ISSUES:

1. IF sound main fuse/s are good.
2. If no power or standby check main fuse, standby power supply and any signsof damage you can see---burnt parts etc.
3. almost all these sets the troubleshooting involves checking voltages on the main power board to narrow down theproblem.
4. Be safe and if you do not know what you are doing don't open the set.

Answers to issues:

1. RE:fuses---if a blown fuse is found get a good replacement(not the genericones like Radio Shack). Many fuses are special even aside from amperage--Don'tput a higher rated amperage fuse in the set for any reason.

2. RE: power supply in set: if total dead aside from main fuse the set uses astandby power supply that runs 7/24 and a main supply (some are combined andsome not.

Here aside from checking fuses you want to examine all the filter caps on thepower/standby to see if any are puffed up or buldged up in some fashion--Iattach a photo of a good one---top should be silver metal and PERFECTLY flatand have no brown material coming out on top or bottom.

What happens in the standby area is they use caps with too low a voltage rating(saves money) which causes them to fail in a year or two---the standby runs7/24 and the heat dries out the caps and they fail.

3. Trouble shooting consists of the above and then at some point you have tobuy and try a board to see if it fixes it or not.

4. Safety first--no TV set is worth getting injured or even killed over.


If the set is opened look on the power supply board for caps puffed up like these--dead giveaway.

If you have questions feel free to comment here--I am not the number one rated expert here for the last six weeks for nothing and I do this here for free.

SD TECH

Check your inputs. The no signal box means exactly that - there's no incoming signal for the TV to decode. So you've either disconnected a cable somewhere or turned off your input device.
Try changing the inputs on the TV (this will be a button saying input or A/V)
Try changing the channels
Check that your cables are correctly connected and that whatever you are trying to use (dvd player, PS3, etc) is turned on.
Check that your TV is tuned to the corresponding input it is plugged in to (if you plugged your DVD player into HDMI input 8, tune your TV to input 8)
Hope this helps.

Need s to be replaced the main board.

This sounds like a PAL vs NTSC problem.
Check that the TV, the DVD and the Player are all of the same system. If not, some DVD players you can choose / change the output system from PAL to NTSC and vice versa.
You may also change the input system of your TV if it does support it.
Let me know if this helps.

According the manual for this TV the remote control has an input button, it is left of the power button. Make sure that the remote mode slected for TV not VCR or DVD and press input button to make a selction, make sure that the power to the DVD player is on. If yours is different try stepping through the channels buttons, some TVs input is selected through the channel buttons.

sanyo lcd dp42647 turns on and has sound no picture black screen

Hi there! The panel may be in protection mode. The Inverter board is the most logical area to start after checking power supply Voltages.(5,6,24 and 13Volts). There may be coils on the Inverter Board which have bad soldering or faulty. Other than this it may be main board which controls switch on or off. If all else fails, refer to a repairer. Beware of High Current!!! Best Wishes and Good Luck, Jus004