Dynex DX-46L150A11 backlight/inverter problem?

[Big Jugs]

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

Ok, more testing to do - I had to format my laptop due to crashes, and am still re-loading things. It will take me a day or so to find a cfl bulb and get the wire attached.

I can't seem to figure out why transformer #12 has a trace connecting pins #1 and #2, but YES this is from the factory. If I can take a picture I will upload later.

[Big Jugs]

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

Looks like I have a blown tube. Was able to get a good look at it in a dark room, and you can clearly see a black stripe through the middle of the screen. I haven't had a chance to hook up the cfl bulb as of yet, but at this point not sure if its going to prove anything.

Now that its somewhat determined that I have a blown tube, what are my options? I would really like to salvage this set, but also don't want to dump a whole lot of cash into it at this stage. Thanks guys.

[budm]

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

If you can narrow down as to which transformer not driving that lamp, then you can try swapping with another transformer next to the suspected one, if the same lamp still look bad then you know you have bad lamp.
One question, how did you manage to get the backlights to stay on long enough for you to take the picture?

[Big Jugs]

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

If you can narrow down as to which transformer not driving that lamp, then you can try swapping with another transformer next to the suspected one, if the same lamp still look bad then you know you have bad lamp.
One question, how did you manage to get the backlights to stay on long enough for you to take the picture?

The tv actually stays on for usually minutes at a time... I've never got the "2 seconds to black" that so many others talk about. Tv stays on for on average 2-5 minutes before flickering slightly and going dark (back lights shutting off), but the timing is completely random.

The tv has 12 transformers, and I was able to count it to the stripe, so its looking like transformer and/or bulb #6 (from bottom) are suspect at the moment.

My resistance check on that transformer came back as around 800 ohms - same as all the others. I can try swapping around the transformers to see if its actually the bulb or the transformer (or try the cfl bulb trick).

Is there a way to bypass that tube (and transformer) all together? It really is not noticeable during regular tv viewing, and I would like to test the set further if I could bypass that lamp to see if the set will stay on permanently.

[selldoor]

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

It would really help us if you could make up a bulb and try the test - it is an unusual
opportunity as your lights stay on. I will look and see if there is a way to trick the
fault detect.

[Big Jugs]

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

Guys, my sincere apologies for the delayed response. I was finally able to get a bulb rigged up and do some tests. I was able to snap a couple of shots, but not many because as soon as I moved the bulb to another transformer, the set would turn off with contact. Even after turning the tv on and off to get it to come back, I wasn't quick enough with the camera to get more pictures.

Anyways, heres what I was able to get.





I believe these two shots were of different transformers. I know for sure one pic is on transformer #6, which lines up with the tube that was not lit from my previous post.

I was able to test a few different transformers (not quick enough to take pics though) and the cfl bulb looked pretty much the same for all transformers.

So I'm assuming I have a blown tube. Is there anyway to bypass that tube and trick the system to stay on?

Thanks

[Big Jugs]

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

Anyone have any ideas how to bypass a blown lamp?

[Big Jugs]

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

Saw a video from Norcal http://www.youtube.com/watch?v=oE6K4...hannel&list=UL who shows how to bypass a lamp in a Samsung set by removing a transformer, and jumpering two points.

This is EXACTLY what I'm trying to do, but don't know which two points I'm supposed to jumper on my specific inverter board.

Hoping for budm or Tom66 to jump in and shed some light on which ones to jumper so I can put some life back into this set.

Thanks guys.

[budm]

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

Your TV does not use the Balancer )which receives the high voltage from the inverter transformer on the power supply-invrter board combo) board like the one used in that Video, you have inverter board which is not the same set up as shown in the video, bypassing that is more complicate since the primary side of the transformer of the one that drives the dead tube must be in the circuit and cannot be removed, the secondary side that has the feedback that is used for telling the circuit if the lamp is in the circuit or not also needs to be disable or fools it to make it thinks there is lamp in the circuit.
This will take some circuit tracing to see how the primary side can be modify to work without one transformer in the circuit.

[budm]

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

This is the exact same board you have?
http://www.shopjimmy.com/media/catal...03.020-top.jpg

[budm]

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

BTW, can you show me the picture of which transformer that is connected to the bad lamp? Tx?

[craigmcduffie]

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

Thanks for the info.

[Big Jugs]

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

This is the exact same board you have?
http://www.shopjimmy.com/media/catal...03.020-top.jpg

Thanks for the reply guys, yes this is the exact same inverter board in my set.

I would say its transformer #6. If you look at the blown up pic from shopjimmy, it says T6 just to the right of the transformer. I've rechecked resistance which checks normal at around 800ohms.

[Big Jugs]

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

BTW, can you show me the picture of which transformer that is connected to the bad lamp? Tx?

Do you want a pic of my exact board and transformer?

[budm]

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

Your board so I can see the transformer that is connected to the bad lamp, or just tell me which T?? is connected to the bad lamp.
You may be able to put the jumpers to fool the circuit to make it thinks it has good lamp connected to it.

[Big Jugs]

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

Its transformer #6

[budm]

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

OK, put a small jumper wire between pin 5 of T5 to pin 5 of T6. Turn on the TV and see if the backlights will stay on, report back what you see. Listen for any high voltage arcing also and be ready to unplug.

[Big Jugs]

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

Ok, will try tomorrow and report back.... thanks budm

[Big Jugs]

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

OK, put a small jumper wire between pin 5 of T5 to pin 5 of T6. Turn on the TV and see if the backlights will stay on, report back what you see. Listen for any high voltage arcing also and be ready to unplug.

I've been hesitant to complete this step - is there ANY confirmation that this is a correct step. I don't want to "fry" anything further and cause un-repairable damage.....

[Big Jugs]

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

Went ahead and made the jumper, installed the jumper following budm instructions from post #37.

Conclusion: No change.

Thought all was well, tv turned on (as it did before) and stayed on for about 5 minutes then went black. Appreciate the ideas, but is there anything else I can try??