I have a sanyo dp42848 turns on perfect picture then goes black you can see picture with flashlight voltage from power supply is present visual inspection of all boards and caps look good inverts ?

There is something wrong with your high voltage LED backlight power supply most likely, possibly a bad capacitor. See if you can identify the part number for the entire backlight assembly power supply and replace it.

your problem is in the power supply since this detects any malfuntion in the inverters do this test first put tv on with no load on inverters if can measure the outut voltage on both sides in and out
up on this you may asume the confliction stage

There is sone short circuted components at its main board. Contact a technician. This is not a user repairable work.

This could be a faulty back light lamp.It is located right at the back of the screen It is an cold cathode lamp supplied by a high voltage from inverter board .Inverter board has a input voltage of 24 volts inverted into 300 volts AC this lamp lights up the screen...
You need to open the back cover to check the lamp.....

Sanyo TVs usually only have two boards in them , doing a visual inspection of the power supply capacitors usually reveals swollen or bulging capacitors.
If the capacitors look good, voltage checks would be needed to isolate the problem to either the main board or power supply. Check for 5 volts to the IR board (& or keyboard) , if five volts is present suspect the main board

I’m happy to help further over the phone at https://www.6ya.com/expert/eric_ab7c09ec01841771

Hold a flashlight to the screen after it goes blank, if you can still see anything on the screen, then it is time to replace the inverter boards (there are 2 of them, VIT71043.50 and VIT71043.51).
Cheers,Stewart

I had the same thing happen to a DP42848 I'm repairing but I could smell ozone on the left side so I didn't replace anything. I just disassembled the screen and found four flouresent tubes not working! I exchanged them to be sure it was the tubes and it was.New screen is out of the question. I am trying to find a broken used LCD screen somewhere and rob the tubes from it as they just snap in and that might not happen so goodbye tv!

Hi,

power supply board is dead, u know basic electronics' and soldering? Most of the times, the power supply board just have dead leakages gases capacitors.These capacitors always bulges up on it top,or puff up on it top.Replaced these gases leakages capacitors will get your TV power stable,and work again.Or tries websites like Shopjimmy.com,Ebay.com to buy a whole refurbish power supply board for the replacement.
Hoping that this will help out in solving the problem

No, there is no power reset. You need to find out now if the backlights inverter baord or the 24vdc from the power supply is good. Bad cap can look normal but can have high ESR (Equivalent Series Resistance).
Please read my guide to understand in more details, it sounds like you may have multiple baords failure.
Basic LCD monitor and TV troubleshooting guide:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague
Parts: www.shopjimmy.com
Parts: http://interliquidparts.com/

Hi art_davis,
Power on the unit in the dark room then shine with the flashlight directly in the screen, you will barely see the images. This is because your backlight is not functioning. The following reason was the caused.
1. Power supply - missing B+(supply voltage) coming from this board feeding the inverter board. This is caused by faulty transistor, dried/leaky electrolytic capacitor, open fusible resistor.
2. Inverter board - even the B+ is good from the power supply, if the fuse, driver transistor, driver transformer is faulty no output to the backlight resulting to black picture.
3. Busted backlight - even inverter board is good but if this is busted resulting to black picture also.

Check the parts here.
Diagnosing the fault is technical and if you don't have necessary tools and test instrument and can't fix it yourself, I would advice you to look for an experienced technician to isolate the problem.
Hope I helped you.
Have a nice day!
Thanks for using Fixya.