SAMSUNG LCD REPAIR TIPS
MODEL: LE27T51B LCD TV
SYMPTOMS: Dark frame with color stripes.
CURE: It's looks like the unstable voltage problem. Check and replace up4 (l1117dg) on t-con board.
MODEL: LE32R73BD LCD TV
SYMPTOMS: No picture and no OSD menu. Backlight ok.
CURE: Reflow LVDS socket on screen driver PCB and mainboard PCB.
MODEL: LE32R74BD LCD TV
SYMPTOMS: TV dead. Pulsating noise from PSU and LED light flashes.
CURE: Check shottky diode DM854 (MBRF1545CT) in PSU for short circuit.
MODEL: LN40A650A1FXZA,LN46A650A1FXZA,LN40A750R1FXZC,LN46A750R1FXZA,LN40A750R1FXZA LCD TV
SYMPTOMS: Unit tries to start with melody but cycles off and back on
CURE: If the unit tries to turn on and makes the startup melody but then immediately shuts off and starts again, unplug the lvds cable and apply power again. If the set stays on, replace the t-con board.
MODEL: LNT4665FX/XAA LCD TV
SYMPTOMS: Lost brightness when you replaced main pcb
CURE: Because main pcb bn94-01199e is designed to work with both models lnt4665fx/xaa and lnt4661fx/xaa when you replaced the board is possible to lost the brightness.go in service mode and turn value lvds byte from 8 to 10.
MODEL: LNS4051DX/XAA LCD TV
SYMPTOMS: Dead backlight flashes on then off
CURE: Unit would flash on then off and audio would work. You could see video with a flashlight. Sometimes unit would stay on and run if you cycled on and off many times. Found bad solder connection on ip board ti801 on primary side. Resoldered and corrected problem.
SYMPTOMS: Unit cycles on/off during startup.
CURE: if the unit tries to turn on but begins to cycle on and off before any video is displayed and all of the smps voltages are good, disconnect the lvds cable at the t-con board. If the set starts and the backlights come on, replace the t-con board. If the set does not start, disconnect the lvds cable at the main board. If the set starts, replace the lvds cable. If the set still does not startup, replace the main board.
MODEL: LNT3253HX/XAA LCD TV
SYMPTOMS: After a few minutes when tv warms-up picture becomes distorted.
CURE: 10-15 minutes after you turned on the unit panel warms-up and picture becomes distorted, If you just push the tv's frame picture becomes even more distorted, On the back of the panel the control asic area is very hot. Replace the panel to fix the problem.
MODEL: LN32A450C1DXZA,LN32A450C1HXZA,LN32A450C3HXZA,LN32A330J1DXZA,LN32A330J1NXZA LCD
Video will intermittently turn mostly white. White display with a faint image of osd and video in the background. Video will intermittently turn mostly white with the osd barely visible in the background. Even a black image or when the panel should not be showing any video, it is white.i found that one of the sub-boards inside the panel, the boards that the ribbon cable from the t-con connect to, are not seated properly and the larger smd capacitors on the board are intermittently making contact with the metal frame of the set, effectively creating a short to ground. This is one of the panels that is mounted upside down, so the stand mounts just below and behind the panel frame. Any slight pressure from the stand can cause the frame to make contact. In many cases, the tv can be slightly flexed to make this issue occur.
CURE: Adding felt to the affected area will solve the issue.
SYMPTOMS: Blue screen without signal, with signal -blue screen with flashing white short horizontal lines
CURE: Replace lvds cable, check if the cable not strangled by the metal cover and loosen up the screws of the cover.