Sony KD-49XE8396 49" Bravia LCD TV

[Jackplug 123]

Hi There,
When this set developed this fault a member of the family passed it on to me,while they bought a newer set.
On power up via the separate 19v SMPSU, a dark screen,backlights and sound OK.
On removing the rear cover later, I checked the TCON board and ordered a replacement just in case.The replacement board made no difference.Prior to replacing the TCON board,I cleaned all 3 ribbon cables with iso prop alcohol.
Disconnecting one of the two LCD ribbons going to the LCD/Gate driver boards,managed to get half a working RHS screen with half the SONY logo "NY"
I have ticked the working LCD cable and crossed the non-working LCD cable.
One connecting only the other ribbon cable showed a faulty half screen with a white RHS half screen.I have attached 4 photos to show results.I have yet to check the LHS LCD/Gate driver board, have read about surface mount capacitors going short circuit which may cause this fault.I dont have a milliohm meter but do have an ESR meter,the Dick Smith electronics kit I bought years ago.
Would also be interested in the "tape trick" and which side of the ribbon cable to isolate?, all input/help appreciated,Regards Steve.

[nomoresonys]

Re: Sony KD-49XE8396 49" Bravia LCD TV

looks like the right side is ok if you are looking at it from the front, tape cut-off method/tapetrick may work, try blocking the first 15 or so pins on the left ribbon cable, see what you get, try left side of cable, no joy maybe try right side of same cable, no need to mess with right cable that side appears to be ok. Figuring out just which ones to block can be very tough, may have to play with how many and which ones get blocked, video example there, this tv wizard only had to block one line, but sometimes more is needed, depending on the short: https://www.youtube.com/watch?v=pfrRhw7-ZII

[nomoresonys]

Re: Sony KD-49XE8396 49" Bravia LCD TV

milliohm meters are very useful indeed, you can also test those little mlcc caps on the panel driver boards for shorts or very low ohms with a standard multimeter.

[Jackplug 123]

Re: Sony KD-49XE8396 49" Bravia LCD TV

Hi NOMORESONYS, thanks for the info.Is is worth also checking the surface mount decoupling capacitors on the long thin board on the left that interfaces the TCON board to the LCD panel.Are there COFs fitted on the ribbon to the LCD screen?Looks like a bit of a job to expose this board many screws to remove along the bottom edge so condition unknown until I do.
One thing I did early on was to perform a reset by holding the power button and vol down while powering up.No change to fault as seen on my pictures.Presume original TCON board was actually OK then?
Regards
Steve

[nomoresonys]

Re: Sony KD-49XE8396 49" Bravia LCD TV

yes those long thin boards are the panel driver boards, kind of a pain to expose them but need to to test those little caps etc.

[nomoresonys]

Re: Sony KD-49XE8396 49" Bravia LCD TV

can just check them in continuity mode, if one or more show continuity with a probe on each end there's a short somewhere, can also check for very low ohms, sometimes they will all read short but only one may be bad and making the rest read short.

[Jackplug 123]

Re: Sony KD-49XE8396 49" Bravia LCD TV

Thanks Nomoresonys, my thoughts on a shorted cap came from a you tube video from Michael Dranfield working on a Samsung Tv,turned out to be just one but he had to use a milliohm meter to narrow the field down.Do the TCON ribbon cables have double sided connections and presumably sellotape will do the job isolating the pins?
Thanks..

[nomoresonys]

Re: Sony KD-49XE8396 49" Bravia LCD TV

usually just one side has the contacts, about any non-conductive tape will do, don't want it too thick tho because you need to latch the connector back down.

[fpegman]

Re: Sony KD-49XE8396 49" Bravia LCD TV

Can anyone tell me how I can put a post asking for advice on this forum please I am a member thanks

[nomoresonys]

Re: Sony KD-49XE8396 49" Bravia LCD TV

pick a category, example this one: Troubleshooting TVs and Video Sources, click forum tools-post new thread.

[Jackplug 123]

Re: Sony KD-49XE8396 49" Bravia LCD TV

Thanks, will try isolating the pins on the ribbon cable and checking for shorted surface mount caps on the LCD interface board.

[Jackplug 123]

Re: Sony KD-49XE8396 49" Bravia LCD TV

There appears to be 60 pins per TCON output ribbon cables

[Jackplug 123]

Re: Sony KD-49XE8396 49" Bravia LCD TV

Just spent a while mapping the 60 pins
starting from the left hand side
pin1
pin2 clock 1
pin3 clock 2
pin4 clock 3
pin5 clock 4
pin6 clock 5
pin7 clock 6
pin8 clock 7
pin9 clock 8

[Jackplug 123]

Re: Sony KD-49XE8396 49" Bravia LCD TV

Finally took a chance and isolated first 9 pins of left TCON ribbon cable ie all 8 clock pins with some hi tech sellotape.
Result full picture.
Saved checking the LHS interface board to LHS of screen.
Now comes the tricky fiddly bit,isolating the faulty clockline.
Am gonna need a bigger magnifying glass!
Picture seems OK but yet to test HI resolution mode on TV.
Thanks to Nomoresonys for his help,especially the sticky tape fix link.

[nomoresonys]

Re: Sony KD-49XE8396 49" Bravia LCD TV

Thanks Jackplug 123, glad it helped.