Ltdn42v68us

[VAPatriot757]

My wife was dropping her Nana off one day when she found a LTDN42V68US on the side of the road with an attached note that read, "Feel free to take and fix." So, since she thinks I can fix anything, she put it in the car and brought it home.

The first was to obviously plug it in and make sure it wasn't something simple and to see if there were any diagnostic indications. The red light comes on steadily and does not blink.

After reading online, it sounded like the power board was the most likely culprit. I ordered a new one from Ebay and after install, I got the same result.

What are my options at this point? Is there anyway to troubleshoot the screen itself or shall I replace the other board next?

Any and all help is greatly appreciated

[budm]

Re: Ltdn42v68us

Please use the managed attachment to upload good and clearly focused pictures of the back side of the TV so we can see how the boards are hook up together first.
What is the P/N of the power supply board? it should be something like BN44-?????

[VAPatriot757]

Re: Ltdn42v68us

Here are the pictures. As far as part number...I'm not sure of where to even look on the board for it as there are many numbers. I ordered the part by searching "LTDN42V68US Power Board."

Thank you for your response, I'm looking forward to hearing your synopsis!

Jason

[budm]

Re: Ltdn42v68us

OK, on the power supply board, there are three connectors with voltage labeling next to them. Can you please take the pictures so we can see what the pins are so we can check the voltages on those pins.

[VAPatriot757]

Re: Ltdn42v68us

Here are the requested photos. Thanks for your time!

[budm]

Re: Ltdn42v68us

OK, Please take the voltage readings on these two connectors of the power supply. Meter set to DC, Black probe on the chassis.
Check with power switch activated and not activated.

[VAPatriot757]

Re: Ltdn42v68us

Now that I'm re-reading my original post, I realize that I failed to mention that the TV will not power on. I get a steady red light in the front but the power button on the unit itself and the remote do nothing. Sorry for the confusion! I will still shoot those wires though right now.

[budm]

Re: Ltdn42v68us

That is OK, just take the reading when you first plug in and take the reading, then hit the power switch and take a reading. I am looking for any voltage toggling. At this point you may have bad main board. I am expecting the STB pin and the SW pin to change state.

[VAPatriot757]

Re: Ltdn42v68us

They both read zero prior to and after pushing the power button. The only pins that register are the 5v pins on both.

[budm]

Re: Ltdn42v68us

OK, those two pins get the voltage signal from the main board, the STBY pin is used to turn on the power supply board, the 12v will be on when it works. The SW pin is for turning on the backlights inverter circuits.
You may want to look for new replacement main board, troubleshooting down to component level will not be practical.
You can test the power supply board function by removing the connectors XP802, XP809, then connect a 1000 Ohms resistor between S5V pin and STB pin, and another 1000 Ohms between S5V pin and SW pin. Plug the TV in to the outlet, you should see the backlights come on.

[VAPatriot757]

Re: Ltdn42v68us

Per your recommendation, I am ordering a replacement main board.

http://www.ebay.com/itm/126524-Main-...item27ce72c341

Thank you so much for your help sir! Greatly appreciated!

[budm]

Re: Ltdn42v68us

Make sure to match the P/N on the bar code.

[VAPatriot757]

Re: Ltdn42v68us

Budm,

I just wanted to say thank you for all of your help! We now have a working 42" tv for $65! The part was so simple to change. My wife is stoked! Thanks again.

[tom66]

Re: Ltdn42v68us

Excellent - Thanks for the feedback!

[budm]

Re: Ltdn42v68us

Thanks for feedback, $65 for 42" TV to watch the Superbowl next week is great! Go Niners!