Panasonic TX-42A400B

[ronhayes]

Hi All
I have this Panasonic in with no picture but has sound and backlights are on ?
I have took some pictures of the panels but I have not removed any as yet all caps look ok on all panels.
I am thinking the fault will most likely be with the T-Con board?
Unless someone has had this fault and knows different!!
Any help much appreciated.
Ron

[ronhayes]

Re: Panasonic TX-42A400B

I have checked the fuse F1 on the T-Con board and that seems ok.
Ron

[vinceroger69]

Re: Panasonic TX-42A400B

as the panel pcb is on the bottom of the tv is it possible someone has cleaned the screen with fluid and damaged the tab bonds? im not sure if this would give you a whole no image situation though do you get voltage too both sides of the tcon fuse

[ronhayes]

Re: Panasonic TX-42A400B

I get 12,2v both sides

[vinceroger69]

Re: Panasonic TX-42A400B

what about it you remove one side of the tcon too lcd panel ribbon cables, do you get a image on half of the screen? try this on both sides of the tcon

[ronhayes]

Re: Panasonic TX-42A400B

Here are some pictures with the ribbons disconnected .
The half white and half black with lines in it is with the right hand ribbon disconnected and the two blank screen pictures are one with the left hand ribbon disconnected and with both ribbons connected.

[ronhayes]

Re: Panasonic TX-42A400B

Sorry if I don't reply after this message as I am now getting ready to go to work as I am on night shift this week.

[ronhayes]

Re: Panasonic TX-42A400B

Going by the results of removing the ribbons it seems that the T-con board is certainly faulty ?

[attainteddragon]

Re: Panasonic TX-42A400B

i think that you have a panel fault with the alternating picture status that you have shown.

[ronhayes]

Re: Panasonic TX-42A400B

Hi All
Was wondering if anyone has a service manual for this set?
I have now tried replacing T-Con board and the main AV board but still have no picture !!
I have back lights and sound but no video any help would be much appreciated.
Or has anyone had one of these sets with this issue ?

[dick_barton]

Re: Panasonic TX-42A400B

Hi Ron,
Available to download from

https://www.electronica-pt.com/esque...s-km25e-32819/


I would strip it down and have a good look at the circuit board which the tcon connects to. This runs along the bottom of the set and also connects to the panel via the tabs. Check that water has not caused any damage.

[ronhayes]

Re: Panasonic TX-42A400B

I have had a good look at the boards connected to the screen and have even eased one of them out without causing any damage to connectors and can not see any water stains at all.
I have asked son for the remote so I can carry out some tests but I am thinking that the display is the fault.

[ronhayes]

Re: Panasonic TX-42A400B

I now have the remote for this set but as there is nothing displayed on screen you cant do anything with it.
Is there any way to test a lcd screen to see if it is faulty ?

[vinceroger69]

Re: Panasonic TX-42A400B

maybe with something like this?
http://www.ebay.co.uk/itm/TV-Laptop-....c100005.m1851

[ronhayes]

Re: Panasonic TX-42A400B

I have just been looking at those lcd testers they look like a good item to have.
Has anyone used these testers ? If they have what do they think of them ?
Are they user friendly to use and what sort of problems can they diagnose ?
Any info would be much appreciated before I go ahead and purchase one.

[vinceroger69]

Re: Panasonic TX-42A400B

This is a good video showing it in action the main thing is i guess would it have all the correct connectors to all the different brand of tv t cons
https://www.youtube.com/watch?v=i4Cq0hNTNIo

[dick_barton]

Re: Panasonic TX-42A400B

If I remember when reading the spec on it some time ago it still has to be connected to the Tcon so it would not eliminate a tcon fault or a coff chip fault. Therefore I think it has very limited use.

[ronhayes]

Re: Panasonic TX-42A400B

Yes I agree it is limited! When watching the video you have to connect it to the T-con board and what he is saying is if you still do not get a display then it is the T-con board.
I have changed the T-con board but still no display.
You would need to be able to connect this tester after the T-con board but they do not show if this is possible , They do show it being connected directly to a laptop screen so maybe you could connect directly to a TV lcd screen but you would probably need a different connector but that could be costly for all different models

[ronhayes]

Re: Panasonic TX-42A400B

I will ask the question to one of the suppliers to see if it is possible to connect the tester directly to a TV lcd to test the screen rather than through the T-con board and see what they say ?

[ronhayes]

Re: Panasonic TX-42A400B

Can anyone advice can a LCD screen lock out after so many hours of viewing ?
For example no display if it has reached the allotted hours ?
I think I read some ware in the past that some screens could only display for so many hours ? mainly LCD's