Dynex DX-46L150A11 backlight/inverter problem?

[nomoresonys]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Well, it's definatily a bad bulb.
I cut the traces that go to two bulbs and swapped them and the unlit bulb didn't move. Inverter is good.
So, the only thing to do is disassemble the display panel.

Taking it apart was easy enough...I just really hate touching the actual display panel (finger prints and all. OK, I have issues)
You can see in the pic the bad bulb. You can also see that the plastic reflectors are pretty crispy (I can paint or put some foil on them). They should be white and you could actually see that in the display.

So, given that one bulb is bad how long before the others go too? And if one is replaced, wont it's color be brighter than the others? The bulbs dimm over time till they die.
This was my mother-in-laws set and she never really turned it off so if I had to guess, the bulbs have 10k to 15k hours on them. They're about done arent they?

CFLWarehouse.com has them for $20 which is $240 for the set. Think it's worth it? Or just replace one, get a little more life from it and stop worring about stuff?

What do you think?
Thanks,
davidk

I think I'd try the 20 dollar bulb Dave spoke of here.

[audiofreak19]

Re: Dynex DX-46L150A11 backlight/inverter problem?

I'm interested in what happens after the bulb. I swapped my bulb and got 2 sec to black. The bulb lights up fine but shuts off. Please let us know what happens when you put a bulb in it.

[jackal68]

Re: Dynex DX-46L150A11 backlight/inverter problem?

I know this is an old thread but i found a guy on youtube who installed a resistor to bypass a bad bulb (2:15 min into the video). However, I am not sure of the resistor value (brown, red, black - i'm assuming it is 120ohm, can anyone confirm)? Also, he mentioned that he moved the bulb from the middle to the bottom; how difficult is it to do that?

thanks.

https://www.youtube.com/watch?v=TO1_pkFNJKY

[nomoresonys]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Moving the tube is a total stripdown job, you might have luck with this method but it leaves the tube where it is, do you know which tube it is?: https://www.youtube.com/watch?v=Dh01ZepjDp0

[jackal68]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Moving the tube is a total stripdown job, you might have luck with this method but it leaves the tube where it is, do you know which tube it is?: https://www.youtube.com/watch?v=Dh01ZepjDp0

I believe it is either the 3rd or 4th one from the bottom (very similar to what the guy had on the youtube video).

[nomoresonys]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Most of the time you don't notice much being one tube down, mostly only when there's a solid color on the screen, fixed one that happened to be right at the top, I only noticed it if I looked really hard but I think that's only because I knew it was there.

[jackal68]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Most of the time you don't notice much being one tube down, mostly only when there's a solid color on the screen, fixed one that happened to be right at the top, I only noticed it if I looked really hard but I think that's only because I knew it was there.

Hi

could I know how you 'fixed' it? Was it using the resistor suggestion on the youtube video or another way? I want to confirm if the resistor is 120ohm or 12ohm. thanks

[nomoresonys]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Look at the video, I believe he used just a jumper wire to bypass the transformer if you are sure you have the faulty transformer located you can just remove it, I bypasses because it was easier for me.

[jackal68]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Okay, i actually ordered another inverter board, but unfortunately, it arrived cracked. Initially, I thought I could use the transformer from the cracked board on my board, but it turns out that the board versions are difference (I assume they are still compatible), so the transformers are actually different as well (see pic). I am wondering if anyone know whether I can still swap the transformers, making sure that the 'proper' connections are made to the board.

I also tried jumping the timer pin to ground, but it didn't work. The tv would still lose the backlight after a few minutes. Lastly, i took out the transformer altogether, but in this case, the light would come on for a few seconds and then turn off.

As I already had the transformer off, I took out another transformer from the same board and swap them, to see if the dark lcd location would change - it didn't. So, i assume that the lcd bulb is faulty. As such, is there anything I can do to bypass the backlight turning off (I tried the jumping pin but didn't work).

any ideas before I dump this tv?


https://

[nomoresonys]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Appears to be something wrong, pretty sure if you have a bad lamp or transformer and you take the transformer out of the equation, the tv should stay on. one lamp down, thinking you either took off the wrong one or you have a whole different issue.

[jackal68]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Appears to be something wrong, pretty sure if you have a bad lamp or transformer and you take the transformer out of the equation, the tv should stay on. one lamp down, thinking you either took off the wrong one or you have a whole different issue.

Maybe there is something else going on. As soon as I take out one transformer, the tv turns on for a second and then the backlight goes out. Whereas, when all the transformers are on the board, i get about 2-5 minutes.

It doesn't matter which of the 12 transformers I take out, the backlight will go off in 1 sec (i've tried 3 of them already).

Do i need to jump some wires so as to bypass the transformer i took out?

[nomoresonys]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Ok, was thinking that this tv may be different, the ones that were successfully fixed all seemed to be samsung as was mine, go back and read the thread, bud tells of some differences in post #29.

[jackal68]

Re: Dynex DX-46L150A11 backlight/inverter problem?

yes, I'm aware of post #29 (I thought you were as well). Nonetheless, thanks for giving me some inputs.

I'm still wondering if I ground that pin with a resistor, whether it will work. I tried grounding the pin without a resistor and there was no change to the tv.

can anyone tell me if that's 12ohm or 120 ohm?

Again, the resistor color is found at 2:23 min of this video below:

https://www.youtube.com/watch?v=TO1_pkFNJKY

[jackal68]

Re: Dynex DX-46L150A11 backlight/inverter problem?

well, i decided to take a chance and solder in a 120ohm resistor (as per the video). It worked! The screen stays on now (even though there is a darker line where the bulb is burnt). It is not very noticeable when watching tv, only noticeable on a blank screen.

For the price of the resistor, this is great to keep my tv alive!

Hopefully, this helps someone else.

[budm]

Re: Dynex DX-46L150A11 backlight/inverter problem?

I look at that video (per jackal68), the resistor look to be 12 Ohm (Brown/Red/ Black), it can be just jumper wire, and he said pin 3, it is actually pin 14 (you can see the Dot on the IC for pin 1 is located), so what he did was to bypass protection circuit. I would keep an eye on that TV and will not leave it on if you are not around to monitor it since protection circuit is no longer in place..That high Voltage for the bad bad lamp is still present and it can arc over.
Basically it is not a fix, it is bypassing the protection circuit, it is like using tin foil in place of the fuse.
There are many video out there about bypassing, but they do not tell you what the bypassing actually done to the circuit and no warning either.

[nomoresonys]

Re: Dynex DX-46L150A11 backlight/inverter problem?

Ok, thanks Bud, there's the difference, the fix in the video I posted and same fix I did on mine was not a protection disable, which I would NEVER do, no sense in burning down the house.

[jackal68]

Re: Dynex DX-46L150A11 backlight/inverter problem?

It is good to know. As this is a tv that will only be used sparingly, i'll keep my eye for the issue and make sure it is not left unattended.

Thanks for the feedback.

I look at that video (per jackal68), the resistor look to be 12 Ohm (Brown/Red/ Black), it can be just jumper wire, and he said pin 3, it is actually pin 14 (you can see the Dot on the IC for pin 1 is located), so what he did was to bypass protection circuit. I would keep an eye on that TV and will not leave it on if you are not around to monitor it since protection circuit is no longer in place..That high Voltage for the bad bad lamp is still present and it can arc over.
Basically it is not a fix, it is bypassing the protection circuit, it is like using tin foil in place of the fuse.
There are many video out there about bypassing, but they do not tell you what the bypassing actually done to the circuit and no warning either.