Emerson LTDn42v68US comes on then shuts off

[BestAmusementsFL]

typically this would be an issue of the backlight inverter (at least from my own experiences) but i've replace BOTH backlight inverter & AV (Main) Board...just trying to verify that i'm not going crazy and that replacing the power supply SHOULD resolve the issue

TV turns on (3 flashes of the standby light) i get the input notification box in the upper right then the screen immediately turns off (yes i lose backlight when viewing this process from the rear) i have some pics attached but don't believe they'll be of much assistance

thanks for any help guys!

https://onedrive.live.com/redir?resi...nt=photo%2cJPG
https://onedrive.live.com/redir?resi...nt=photo%2cJPG
https://onedrive.live.com/redir?resi...nt=photo%2cJPG

[Agent24]

Re: Emerson LTDn42v68US comes on then shuts off

Have you checked if the image is still on the screen when the lights are off? (Shine a torch on it etc)

Did you check all the supply voltages and see if they are OK and if any change between working and after it shuts off?

It could be the power supply, eg: bad output capacitors, but also bad lamps could be triggering an inverter shutdown.

[BestAmusementsFL]

Re: Emerson LTDn42v68US comes on then shuts off

Haven't checked with a flash light....will attempt that tonight when I get home....I checked the 16v pinout and that was accurate ~+/-3v

[BestAmusementsFL]

Re: Emerson LTDn42v68US comes on then shuts off

okay so with a flashlight i can see the set is working properly...i can change channels and bring up input menus and so forth...would that lean back towards the inverter backlight board then?

[Agent24]

Re: Emerson LTDn42v68US comes on then shuts off

It leans towards the inverter shutting down, which could be due to bad inverter or bad lamps.

Since you already changed the inverter, it would suggest there may be a bad lamp(s) somewhere. (or bad lamp connector\wiring etc)

[budm]

Re: Emerson LTDn42v68US comes on then shuts off

It can be inverter transformers, POWER MOSFETs that drive the Inverter transformers, bad lamp sockets due to corrosion.
BTW, do not the remove the black plastics that the inverter board sticks into, they are sockets to hold the lamps in place.

[BestAmusementsFL]

Re: Emerson LTDn42v68US comes on then shuts off

and essentially with bad lamps tv = junk/target practice

[budm]

Re: Emerson LTDn42v68US comes on then shuts off

Instead of junking it, you can learn about troubleshooting, it will be a good practice on how to take the panel apart to inspect the lamps and see how the panel is put together.

[Agent24]

Re: Emerson LTDn42v68US comes on then shuts off

Instead of junking it, you can learn about troubleshooting, it will be a good practice on how to take the panel apart to inspect the lamps and see how the panel is put together.

x2 - also, lamp replacement is not that hard actually. Just go slowly and carefully so you don't damage the panel.

[BestAmusementsFL]

Re: Emerson LTDn42v68US comes on then shuts off

anyone have a vendor to grab the lamps from? most of my boards i usually get from shopjimmy or tvpartsinstock but have never had to do a lamp swap...are they solder on or do they plug into a socket?

[Agent24]

Re: Emerson LTDn42v68US comes on then shuts off

I think yours are the plug-in type.

I haven't bought any lamps for TVs but I have bought several for LCD monitors. First ones I bought were from CCFL Warehouse but they are expensive.
The rest I have bought from Chinese sellers on eBay for much lower cost.
You can probably find someone on eBay that sells them. Just look around a bit first, because prices can vary a lot.

First of all you have to find out if any are actually bad though.