technosonic lcd3201s

[senndogg]

this is my first effort to repair a lcd tv. i have managed to repair several pc displays, everything thank to you.
this tv has the known "2sec to black" issue. i have read the FAQs and i know the basics but since im new to TVs i would need some advice, tips and tricks.
this tv has been opened before because it had caught fire due to external factors. (a candle fired the antenna cable which burned the 75ohm connector). but the 2sec to black came months later.
you can see the pics and first thing, the CCFL and inverter test is a bit "difficult" to do, cos i think ill have to dismantle all the tv structure, process which i want to postpone as much as i can. (as i am not used dealing with huge panels)
first thing in my hand is the power board. steady 24V and 12V. when power button is pressed a 3,3V is shown at the pin "LCD ON". even when i unplug the inverter connector, 3,3V is there when i press the power button. should i go further and dismantle to go to the inverter board and CCFLs or it can be power board related?
some pics of what can i actually capture.

[tom66]

Re: technosonic lcd3201s

You would need a picture of the inverter boards. There are usually one or two, on each side of the TV. The part # on some of the boards looks a lot like Darfon, and those inverters have very high failure rates (and are easy to repair.)

[senndogg]

Re: technosonic lcd3201s

god saved this tv for not breaking anything.... i cautinously (but blindly) took all pieces apart. now i have access to everything.
this is the inverter board, all inverters show 2.15 kOhms except the seventh which shows 2.55 kOhms. after some minutes im gonna plug everything and see how many CCFLs do light.
another question, what is this 2pin connector which goes to the inverter board? some kind of sensor?
anyway, im gonna let you know.

[budm]

Re: technosonic lcd3201s

The Connector with the black and white wires are the lamp return wires.
Please also look and see if the lamp assembly has any ballast caps in it also and see if they are bad. Example:
http://s807.photobucket.com/albums/y...nt%20FLX-3210/

[senndogg]

Re: technosonic lcd3201s

at the moment no more 2sec to black, but as you can see one CCFL which is fed by the seventh inverter doesnt lit.
next step?

[tom66]

Re: technosonic lcd3201s

Swap the connectors for the seventh and eighth tubes around and see if the tube lights. If the tube lights and now the eighth tube doesn't then the inverter is at fault and most likely it's that transformer.

The 2.55k definitely sounds like a faulty transformer but that test will confirm it.

It looks like you've got a Chi-Mei inverter but it has Darfon parts on it - I recognise those transformers.

Be -extremely- careful with the LCD as it is very easy to damage.

[senndogg]

Re: technosonic lcd3201s

thanx tom. i followed my logic and just did it.
the tube lights when connected to other another inverter and the couple of CCFLs connected to the "faulty" seventh inverter, lights only one of two.
solved: inverter no 7 faulty!
where can i get that?

[tom66]

Re: technosonic lcd3201s

thanx tom. i followed my logic and just did it.
the tube lights when connected to other another inverter and the couple of CCFLs connected to the "faulty" seventh inverter, lights only one of two.
solved: inverter no 7 faulty!
where can i get that?

What's the part number on it? 4xxx or 6xxx?

[senndogg]

Re: technosonic lcd3201s

4xxx. googled but showed nothing
could only buy the entire board.

[tom66]

Re: technosonic lcd3201s

4xxx. googled but showed nothing
could only buy the entire board.

Rest of part #?

[selldoor]

Re: technosonic lcd3201s

Its a 4003L isnt it

http://www.ebay.co.uk/itm/4003L-CCFL...item460194fce0

[tom66]

Re: technosonic lcd3201s

You tell me! What is the full part number?

[senndogg]

Re: technosonic lcd3201s

yes! photo in the link is incorrect, it is exactly like this http://www.ebay.com/itm/4003L-Invert...ht_1526wt_1396

[senndogg]

Re: technosonic lcd3201s

4003L 614078 (GP). but it says works for all 4003L models.

[budm]

Re: technosonic lcd3201s

I think you have found the problem, these DARFON Inveter board most of the time had bad transformers in them.
http://lcdparts.net/TransformerDetai...ProductID=2731
Very cheaply made.

[selldoor]

Re: technosonic lcd3201s

You tell me! What is the full part number?

My belief is that only the first 5 digits are relevant, the rest being manufacturers information dates batch codes etc.
The whole number is however quite clear in Senndoggs pictures. I am sorry if the pic in the ebay link confused anyone - I didnt even look at it. I expect he has used the same picture for all his Darfons as he has a large range.

[senndogg]

Re: technosonic lcd3201s

My belief is that only the first 5 digits are relevant, the rest being manufacturers information dates batch codes etc.
The whole number is however quite clear in Senndoggs pictures. I am sorry if the pic in the ebay link confused anyone - I didnt even look at it. I expect he has used the same picture for all his Darfons as he has a large range.

thank you!

[senndogg]

Re: technosonic lcd3201s

I think you have found the problem, these DARFON Inveter board most of the time had bad transformers in them.
http://lcdparts.net/TransformerDetai...ProductID=2731
Very cheaply made.

thank you too!

is there any possibility to repair an inverter?

[tom66]

Re: technosonic lcd3201s

thank you too!

is there any possibility to repair an inverter?

The repair involves replacing the transformer which costs £10. I have done it twice before on Darfon boards. All you need is a soldering iron, some solder and a bit of patience. I generally stick the iron under each pin and lightly pull them up until the old transformer is removed. Then, I replace the transformer and solder opposite corners down, then the remaining pins. Take care to replace the transformer such that it is the same way as it was before, there's usually a dot on it indicating alignment.

[senndogg]

Re: technosonic lcd3201s

thank you tom. i have the inverter in my hand right now. i was asking in fact if i could repair the defective inverter, but as i see its not possible.\
cheers.