How To Repair A Damaged Circuit Board

T'Con boards
Sony T'Con lath

Samsung T'Con board

DIAGNOSING A FAILED T'CON BOARD

   All video inputs received by the video process circuits are handled on a frame-by-frame basis.  The video frames are converted and scaled to 8 to 10 fleck RGB information.  Information technology is virtually incommunicable for the video process circuit to cause a problem on a specific expanse of the screen.  Failures on this board ordinarily appear every bit distortions, color level shifts, video level shifts or noise that involves the entire picture.  The T'Con can generate symptoms that appear to be video process related, but the video process excursion cannot produce the symptoms of a failed T'Con lath circuit.
T'CON FAILURES

   Failures in the timing control circuits of the T'Con tin can produce symptoms of absolutely no video or generate lines and patterns that usually comprehend all or a substantial function of the screen.  Determining if the T'Con is the cause of a 'No Video' status is a chip more difficult since there are no indications on the screen to clarify. Many of the Sony TV models ove the last few years will detect a T'Con that has completely failed.  The communications data between the video process circuits and the T;Con will cease to communicate, iif the T'Con fails completely.  This volition cause the TV to shut down and display a diagnostic code, indicating a failure of the T'Con.  Not all chassis designs have this feature and it is not found on older models.  The typical scenario when this failure arises is for the technician to bring a video procedure board to the repair location.  Information technology is usually safe to assume that the problem lies on the T'Con board, if the replacement video lath dos not give a solution to the trouble since it is highly unlikely that a replacement board with the aforementioned failure was received.  1 trick to check most T'Cons for functionality is to loosen the LVDS connector at the T'Con while unit of measurement is turned ON.  Handle the LVDS connector with care and be certain to fully release the lock tabs.  Gently rock the cable in and out of the connector while observing the screen for whatever response.  Depending on the chassis, the symptoms of the screen ma be gentle white flashes, intermittent coloured lines, or a screen total of random patterns.  The idea at this signal is to provoke some kind of response on the screen.  Some other helpful procedure is to speedily heat and/absurd the T'Con with a hot air devices or circuit coolant and sentry for patterns appear on the screen.

LVDS cable failures

Although the problem with LVDS cable or connectors can generate symptoms of T'Con failures this unremarkably tends to be intermittent and wiggling of the connectors will usually provoke  a change in the symptom on the screen.  LVDS cable and connectors accept became rather robust over the past few years.  Technicians who damage them crusade most problems and this is by and large quite oblivious upon shut examination.

LVDS CABLE

LCD panel failures

Some LCD panel failures could perhaps mistaken for T'Con board issues.  Other than impairment to the LCD glass, well-nigh console failures are isolated to a particular area of the screen.  Since the T'Con disperses the pixel data to groups of line and column dirve IC's situated on the outer edges of the panel, it is unlikely that more than one of these IC's would neglect at the aforementioned fourth dimension.  Multiple columns of struck on or stuck off pixels are therefore, more likely to be the fault of the T'Con circuits.  The same applies to a single row of lit or unlit pixels.  The T'Con just cannot cut out a single line of data.

T'CON REPLACEMENT

   In many instances, replacement of the T'Con lath will exist relatively straight forward.  In some example, the other boards may accept to be loosened or removed to allow admission to the mounting screws and clearance to remove the T'Con board.  The issue of nearly concern is keeping rail of the heat transfer pads, stand up offs and insulators.  The T'Con is heavily shielded and it si ease to accept one or more of these components accidentally autumn out of the associates when removing.  T'Con assemblies that apply multiple heat transfer pads must exist removed slowly and every attempt must be made to keep the shield and circuit board together as they are removed from the unit.  Check for any service bulletins pertaining to the model and panel design that comprise the subject field lie of 'T'Con estrus transfer pad locations' for pictures to show the proper location of these components.  This site itself has covered disassembly procedure to some model LCD TVs, hither.  Pull up older posts hither, or see the site in Timeslide option, which tin be accessed past the drop down  at the summit left side of the display window.  Information technology will brand search the hands.

Remove the screw from the LVDS cable ground strap so the cable can be moved away.  Unplug the connector to inverter lath and remove harness from the servant.  Remove all screws securing the lath sub-chassis to the panel.  Pull the top of the lath toward you and downward to allow access to the bottom screws securing T'Con.  The position of screws, and disassembly method may vary set to ready.

   Advisedly unpeel the conductive record from the elevation bracket taking intendance not to tear them.  Get out the tape attacked to the T'Con shield.  Remove the top subclass roofing the gate and source driver components.  This will allow access to the upper flat cable connectors, if any.  Carefully elevator the locking tabs securing the apartment cables.  Leave the fat cables fastened to the T'Con and shield donkey;y.  the T'Con board will have an insulating pad between it and the LCD panel that volition cause the board to stick.  Not much effort is required to release it.  The goal at this point is to remove the board and shield together so equally to avoid dropping heat transfer pads and insulators located between the front end of the lath and the shield.  If successful, Both components should stay together as insulated.  Note the spaces mounted on the backside of the board.  These will need to be transferred to the replacement board.  Lift the excursion board upward slowly while observing the location of the heat transfer and insulating pads.  In near cases the heat transfer pad will remain attached to their appropriate ICs and the insulating pads will be struck to the shield.  If anything falls off, apply the education to return them to their proper position.  Transfer all rut and insulating pads along with the flat cables to the replacement board.  Once the components have been transferred to the forepart of the circuit board, attach the shield and flip the associates.  Transfer any spacers or insulating pads to the replacement bard.  Temporarily secure the T'Con board to the shield with electrical tape.  This helps in preventing movements of the circuit bard while installing the associates back into the LCD panel.  One time the T'Con ass'y is secured to the panel, insert and lock the flat cables.  Plug in all connectors and secure the board sub chassis.  Practise not forget about the wire harness that was removed from its servant.

Source: https://electronicshelponline.blogspot.com/2013/06/how-to-diagnose-failed-tcon-board-how.html

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