Dynex DX-LCD26-09 No Picture

[danriis]

When turning on this LCD TV the screen comes on but no picture. All I get is a black screen but it is lit, not 'dead' black. Sometimes it will also show some crazy lines or just a variation in the black color to a sometimes almost white-ish color.
Also, it's like there is a white rim around the edge of the picture, however this rim was also there when the TV worked and is particularly visible on a black screen.
I have done much reading here and elsewhere, mostly interested in at least isolating the bad board or panel, or even a component level repair is ok as I am fairly handy. But it just seems like I see conflicting points on T-Con vs. Inverter or Panel and I don't really know what path to take.
All I have done is some basic testing on the power cables going from Power board to Inverter and Main board. Generally the voltages are close but kind of low.
Where the board calls for 24v I get 23.3v (to inverter)
Where the board calls for 5v I get 4.9 (to main board)
Where the board calls for 12v I get 11.8 (to main board)

Would love to hear suggestions on where to start testing...
Or is there a real comprehensive troubleshooting guide that lists steps for testing LCD's?
I have found a lot of info but nothing really organized in a step by step troubleshooting approach.

thanks so much, I sell used electronics for a living and I am actually trying to learn enough to start delving into the LCD/Plasma realm as well since we can get broken units for $20 each all day long :-) As mentioned, even isolating a bad board is enough since most are available on Ebay or elsewhere used at reasonable prices.

Dan

[Phaihn]

Re: Dynex DX-LCD26-09 No Picture

post good clears pictures "use the go advanced button.

[budm]

Re: Dynex DX-LCD26-09 No Picture

OK, your chassis looks like this?
http://s807.photobucket.com/albums/y...20DX-LCD26-09/
I would suggest you to look at the T-CON board which sitting under the metal shield at the top center of the screen with ribbon cable attach to it and the main board. Need to check the surface mounted fuse and voltage on that T-CON board.
Also inspect the caps on the power supply.

[danriis]

Re: Dynex DX-LCD26-09 No Picture

Thanks for the repsonse!

The pictures look like mine, but interestingly enough not the same t-con board.
I have attached a picture of mine, I am guessing it's that long narrow one along the top edge of the set, perpendicular to all the other boards? That's where the ribbon cable goes to.
Not sure how to get it out but looking down the side of it I could see the letters FP1 next to a fuse, I tested it and it was fine.

I turned on the set and read the voltages coming out of the ribbon cable where it attaches to the (presumed) T-con board. Is that where you meant for me to check?
4 times (all next to each other) I found 11.8 volts.
3 times I found 1.3v
3 times I found 1.0v
1 time I found 1.2v
1 time I found 1.1v
The remaining ones have no voltage on them.

All caps on all the boards look good. I have an ESR tester coming in the mail, seemed like a worthwhile investment to make sure.

Would love to hear your thoughts on next step, thanks so much for the help,
Dan

[Phaihn]

Re: Dynex DX-LCD26-09 No Picture

i think some of use would like to see some clear closeup pictures of the rest of the set and componants.

[budm]

Re: Dynex DX-LCD26-09 No Picture

You have one those not to be repaired integrated T-CON/LCD panel assembly. The voltage feeding it is present so the circuits on that T-CON need to be troubleshoot, you will have to disassemble the LCD panel so you can get acces to the test points, voltage regulators, switching power supplies on that T-CON board. Not sure if it is worth it for 26" TV.

[danriis]

Re: Dynex DX-LCD26-09 No Picture

Got it, I have 10 other large LCD's and Plasma's sitting here so I will choose a Toshiba Plasma or Sony LCD to learn on next. I picked this Dynex first because if I broke it then it would be no big deal, but apparently it is too lowly of a set to even be broken by me!!! :-)

But again, where to start, is there any organized written approach to troubleshooting or a sympton guide to help get started in the right place?
Thx for all the help,
Dan