toshiba lcd backlight is on but no picture?

[mzone]

hi

i have a Toshiba 46ZV555DB set powers up and i can see the backlight lights the whole screen up ok.

fault is that the backlights are on but theres no picture or osd or anythink just backlight.

anyone have any ideas what it might be or know a link for service manual for this set.

thankyou

[michael first]

hi,if the sound is ok,you should consider the T-con board as the defective one.also try to disconnect and reconnect the LVDS cable from the main board to T-con.if it doesn't sort any result might have a defective main board.cheers

[WILLYAM1]

hi.
check with scope video signal in lvds cabel in main board if ok t con is defectiv most of the time its smd fuse.
 willyam1

[mzone]

thankyou for the help guys.

yes tv still has sound, very rarely the picture will come on, but noticed theres a ghosting on the screen  menu.

im guessing this is the T-con board? ( picture attached )

the number on the board is 4046fm1m4c6lv0.2

googled nothink came up for that board number?

[mzone]

after some further investigation i managed to get a picture on set, from trying blind with remote to switch av settings i managed to get picture to come on when tv is on normal tv av channels 1-5

however soon as you switch to hdmi, or scart av the lcd reverts back to just blank screen with backlight on, so this might point to main board problem.

i have also noticed when the picture is on in the middle of screen theres thin black lines showing across mid of the screen and also there seems to be a mirror image showing at at bottom, i have attached a couple of pictures showing both faults.

would the main av cause this fault?    or has anone come across this problem before?


thankyou

[brainstorm]

Hi,

It does look like a TCon board fault, but what I would is to feed the the scart out of the Tv into another set and see if the fault is showing on the 2nd set, if it is then it is probably an AV board fault and if it isnt then it is probably an TCon board fault.

This method isnt foolproof but i find it works 99% of the time

Brian

[mzone]

thanks brainstorm, never thought of that i gave it a try.

i tryed what you said.

i hooked it up from scart off tosiba lcd to a small portable tv with scart i also connected a component cable input from a dvd player, i can hear the dvd player playing on the lcd tv but blank picture and just snowy on 2nd tv, however if i press the freeview digital button on the lcd and switch tv to digital i get a picture on the 2nd tv of the freeview option but still blank picture on lcd tv so would you say t-con? picture comes on ok on digital with no faults showing.

i can not get a picture on 2nd tv when lcd is fed with a component input.

[brainstorm]

Hi,

If Freeview picture is ok (2nd Picture) on 2nd Tv but blank on the Toshiba LCD then I would say it is more than likely a faulty TCON board.

If you are playing a DVD then you would probably have to scart it into your Toshiba LCD to then get it to output on to your 2nd TV(that way it would auto switch via pin8 of scart)

I dont know if the TCON board is available as a seperate item or not, I presume you have checked for open circuit SMD fuse on Tcon board?

If you are stuck (Try CHS) then let me know and I will try to find out if it is available and part number etc

Brian

[mzone]

hi brainstorm yes the smd fuse is fine, i looked on chs they do stock this t-con but want a stonking £275 pounds   :chok: cant seem to find a cheaper alternative. :unknw:

i would be very gratful if you could possibly find out if this board is avalible please or if theres a substitute part.

i also forgot to include i have noticed the lds cable from the main tuner mainboard goes into another board before that boards 2 lds cables feed the t-con board but unsure what this board boards purpose is?

i have attached a picture showing both boards.

thanks

[brainstorm]

Hi Mzone,

Wow this is an unconventional chassis! I have looked at it and the board that is feedinging the TCON board is called the Haniel Charis board! (not a board I have ever heard of before) It is the one marked PE0624. I think you will need a Schematic diagram  to work on this further.

The part number is 75013861 for the Haniel Charis board.

The TCon board is not showing in the service manual, so it is probably part of the LCD screen

I have tried to attach a couple of extracts from the manual to help you, Im not very good at the computer bit so I hope they are legible!

Brian

[brainstorm]

Hi
Sorry 2nd doc didnt attach!

[brainstorm]

Hi,

Well that didnt work very well!
I have emailed the zipped manual to you

Brian

[mzone]

thanks brainstorm  tryed to view manual but get a error This Service Manual requires ZEUS ENGINE.

regarding the Haniel Charis board can i ask whats the purpose of this board? ?


would you say problem lies with this board or do you still think t-con?

[brainstorm]

Hi Mzone,

I was worried that opening the manual would be a problem!

I have never come across a Haniel Charis board before, so I am in the dark as much as you!

i presume it is for some extra processing purpose?

I will have to try and print extracts from the manual and then scan them and try to post them here.

Please be patient I will get them on here as soon as i get chance

Brian

[brainstorm]

Hi ,

i managed to get one of our IT whizz kids to "print screen" the docs

Brian