Sanyo DP42848 Sound - No Picture

[krseaman]

Tv powers on. After 6 seconds, picture comes on w/ faint buzzing sound from each inverter board equally - for 1 second then goes away.

Picture is visible in LCD with a flashlight.

I've attached a couple of pictures, let me know where I should start!

Kevin

[krseaman]

Re: Sanyo DP42848 Sound - No Picture

Here are pictures of the inverter boards, dark spots look to be Flux not Charred.

[krseaman]

Re: Sanyo DP42848 Sound - No Picture

I checked the Voltage to the two inverter boards and i'm getting 24V to both the master and the slave. If i unplug the slave inverter, and leave the master plugged in, i get the same behavior: turn on, 6 seconds later light comes on for 1 second, then off.

[budm]

Re: Sanyo DP42848 Sound - No Picture

I would Ohm out all four MOSFET's (the device with tab and 3 pin, the middle pin is connected internally to the tab), just label each pin with 1, 2, and 3. Then check the resistance between
1&2
1&3
2&3.
I would also replace those 3 caps on each inverter, it is cheap to do, need or not so you will not have problem later on.
Also look real close at all the solder joints and for any burnt components.
Set the Ohm meter to about 2K scale.

[fading fast]

Re: Sanyo DP42848 Sound - No Picture

i have two of same tv same problem. when both sets come on you can see dark sections across screen like the lamps are burned out in that area. dont believe there is anything wrong with inverter boards

[selldoor]

Re: Sanyo DP42848 Sound - No Picture

@fading fast - you will need to open it up and try and check if all the lamps light, could be lamps or wiring.

[krseaman]

Re: Sanyo DP42848 Sound - No Picture

I swapped out the master inverter with a known good board and left the slave unplugged, and it does the same thing. So i also think its not a problem on the Inverters....

Would bad bulbs make it come on and go off? The Entire screen lights up and looks normal for 1 second before going off.