How do fix my 42inch Sanyo tv wen you turn the power on the green lite comes on then go's off after 3or4 sec

First thing I would try is replace whatever cable you are using for the input. Or just turn the TV on and press the input/source button on the remote then move the input to see if you get anything different.

This is very likely a power board problem. Remove the board and inspect the capacitors for problems like a blown or expanded electrolytic capacitor. This is a common problem with TV's that age beyond their operating life of a few years. I have replaced many TV power boards that I own and for computer monitors with the identical issue.

Fault with the main power supply regulator board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
http://electronicshelponline.blogspot.com/
It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time.

Might be a problem with PSU or some of sustain board. Nothing you can fix by yourself. requires service

Not true that its def the power. Mine did the same thing. Green light, no sound or video. Replaced the power board with same results. Waiting on main board now.

This is a protection circuit that prevents the tv from coming on (to stop damage of the components) ....you need to check your voltages off the power supply and make sure they all read well (EX: 24v12v5v etc). Also look for popped capacitors that would make the values lower than need be for the tv to power on properly.


Once you repair the power supply then you may need to replace other components if needed (EX: backlight inverter)! The backlight inverter is what lites the screen for viewing!

I would recommend to repair immedately and stop trying to turn it on over and over...this will futher damage your tv and cost more to repair in the long-term.


Please rate if this helps! :D

if you have comcast you can use your remote to change the setting to DVD and then change it back to cable. your picture should then come back

unplug the power connector to the tv, wait two minutes then plug it back in and try to turn on the set... this worked for me.

yeah, should stay red when unit is turned off, indicating there's power but it's doing nothing.

Per user manual:
Solid red - power off (standby mode)
blinking red - power off (now cooling)
blinking green - power on (preparing to light lamp)
solid green - power on

It could be several issues from a bag power supply, the TV is connected to a power strip with several other components hooked up (DVD, Sound System, Xbox, etc.).

Try connecting to the wall directly and see if it now starts up.