Sony klv 32u300a display problem

[abbas101]

I have problem with my above SONY LCD TV, as you can see in pix that its 1/3 lower portion is darker then rest of display. Can someone suggest,

We swap 4 inverters transformer from lower portion to upper one but it makes no difference. How can I check if some of the CCFL tubes are weakened or blackened without opening the panel. Your help will be appreciated

[Pentium4]

Re: Sony klv 32u300a display problem

Upload some clear pictures using the attach function

[abbas101]

Re: Sony klv 32u300a display problem

[tom66]

Re: Sony klv 32u300a display problem

...Can you try with a solid white screen so we can see exactly how and where the picture is dim?

[abbas101]

Re: Sony klv 32u300a display problem

Pictures are attached
Pixs are taken with graphic card connection removed.
brightness was set to maximum before removing card connection.
I dont know how to get white background.
Hope these pictures will serve the purpose
Your further advice will be appreciated

[tom66]

Re: Sony klv 32u300a display problem

Does this set use twin inverters?

[abbas101]

Re: Sony klv 32u300a display problem

Tom, set is with technician and although he is good with crt tvs and sound hands, he is not comfortable with LCD's. Can you please be more precise as what should I ask him? He may not be familiar with term twin inverter. He although show me a card with lot of (8 or 10 transformers soldered on it, and latter he swapped some of them)

[tom66]

Re: Sony klv 32u300a display problem

A picture of the back of the set would tell me if it uses twin inverters, also one of the PANEL STICKER (which has who made LCD panel, e.g. "AUO", "Chi-Mei", "S-LCD", "Samsung", "LG Display"...)

[abbas101]

Re: Sony klv 32u300a display problem

After replying to you I left for technician shack and got picture of back panel,It uses two transformers per tube, For Label I will visit tomorrow and will let you know.
Appreciate your help

[abbas101]

Re: Sony klv 32u300a display problem

Tom, does this panel sticker is affixed on back of lcd panel itself or somewhere else?
Do we have to remove all boards?

[abbas101]

Re: Sony klv 32u300a display problem

Please also note three transformers at top
These are blackened at middle.
Actually they were soldered at bottom, but technician move them to top.
But it did not solve problem

[tom66]

Re: Sony klv 32u300a display problem

I suspect some bad bulbs in the panel or the connectors are loose at the other end. You would need to take the LCD panel apart to get to the bulbs.

[abbas101]

Re: Sony klv 32u300a display problem

Is there any method by which we can check from outside if tubes are ok or not (by using multimeter etc)?

[abbas101]

Re: Sony klv 32u300a display problem

Would you call it twin inverter?

[abbas101]

Re: Sony klv 32u300a display problem

Would appreciate feedback from other veterans also

[tom66]

Re: Sony klv 32u300a display problem

You won't be able to see if they are loose without having the panel apart but my personal opinion is that there are bad bulbs or a loose connection on the bulbs.

It does not appear to have two inverters (twin inverter or master/slave inverter.)

[abbas101]

Re: Sony klv 32u300a display problem

I am now looking for ccfl tubes, as soon as I get couple of them, we will proceed with dismantling of LCD panel. In the mean time if any one come with some suggestions, it will be highly appreciated

[tom66]

Re: Sony klv 32u300a display problem

No point ordering bulbs unless you are sure the bulbs are bad.

[abbas101]

Re: Sony klv 32u300a display problem

Tom, Thanks for your comment. I really appreciate your consideration. Problem is that, that technician is not interested in dismantling the panel until and unless he is not 100% sure that it is CCFl tube or loose connection which is causing problem.

He wish to have at least couple of tubes in hand so as if we found any fault with tubes it can be replaced immediately and panel should be closed immediately without wasting time as he had very bad experience where he left one panel unattended and accidentally it was cracked.

Is there any way by which we can turn on tubes one by one from outside with out dismantling?

[abbas101]

Re: Sony klv 32u300a display problem

Please advice what these RJ?? components are with "0" printed on top, are these resistors with 0 value and acting as jumpers?

There are lot of these on inverter board and all showing continuity except RJ58

Any advice?