Sony Bravia TV Repair Guide — Fault Codes, Main Board & Power Supply

This guide covers Sony BRAVIA TV diagnostics and repair — from software resets and blink code interpretation to board-level fault finding. Written for home users and professional technicians alike, covering LED, LCD, Android TV, and Google TV models.

🔍 Sony Bravia TV Architecture — What’s Inside

Understanding which board does what is the foundation of fast, accurate Sony TV diagnosis. Most Sony Bravia LED/LCD models contain these main assemblies:

• Main Logic Board (Motherboard) — the TV’s brain. Controls HDMI inputs, Android TV / Google TV software, audio/video processing, Wi-Fi, Bluetooth, and communication with all other boards. Part numbers typically printed on a white sticker on the board itself.
• Power Supply Board (PSU) — converts mains AC to regulated DC voltages for the main board, T-Con, and backlight LED driver. Often the first board to fail on older Sony models.
• T-Con Board (Timing Controller) — converts video signals from the main board into pixel-level timing instructions for the LCD panel. On some slim Sony models it is integrated into the main board.
• Backlight / LED Strips — LED arrays inside the panel chassis that illuminate the screen. Powered by a dedicated driver circuit on the PSU.
• Inverter Board — present on older CCFL-backlit Sony models. Generates high-frequency, high-voltage AC to drive fluorescent backlights. (Not present on LED models.)
• Panel — the display itself. Passive — it only responds to T-Con signals and backlight power.

🔴 Sony Bravia Red LED Blink Codes — Full List

When a Sony Bravia fails to start, the red standby LED blinks a repeating pattern. Count the blinks in one sequence before the pause — this is your diagnostic code. The codes below apply to most KDL and KD series models; some codes can vary slightly by model year.

How to count correctly: Observe in a dark room. Watch the front standby LED. Count the blinks, then wait for the ~3 second pause before it repeats. Confirm the count two or three times.

🔦 The Flashlight Test

This test tells you immediately whether the panel and main board are producing an image, and only the backlight has failed — essential for diagnosing 4 and 6 blink codes.

1. Power the TV on and wait 30 seconds.
2. In a dark room, shine a torch at a sharp angle directly onto the screen surface.
3. Look closely for a faint menu, logo, or image.

• ✅ Faint image visible — Panel and main board are working. Backlight or its power circuit has failed. Focus on: PSU backlight driver, LED strips, or inverter board (older models).
• ❌ Completely dark, no image — Main board is not outputting a signal, or the panel itself is faulty. Focus on: main board, T-Con, or panel.

🛠️ Step-by-Step Diagnostic Workflow

Step 1 — Power Reset (Always Try First)

1. Unplug the TV from the wall outlet completely.
2. Press and hold the physical power button on the TV body (not the remote) for 30–60 seconds.
3. Wait 5–10 minutes.
4. Plug back in and power on.

This drains capacitors and clears transient faults. It resolves many 5-blink and boot-loop issues, especially after power surges.

Step 2 — Special 8-Blink Reset

For 8-blink codes specifically, Sony recommends a dedicated reset procedure. With the TV plugged in but in standby:

1. Hold the Up arrow button on the remote.
2. While holding it, press and release the physical Power button on the TV body.
3. Continue holding the Up arrow button until the TV resets.

This forces a factory-level reset that can clear audio protection faults without full data loss.

Step 3 — Remove All External Devices

Disconnect all HDMI, USB, satellite, antenna, and external speaker cables. A faulty external device pulling down a voltage rail can trigger blink codes that appear to be internal board failures. Re-test with nothing connected except mains power.

Step 4 — Visual Inspection (After Opening)

With the back panel removed, inspect all boards for:

• Bulging or leaking capacitors — the top of the cylinder appears domed or shows residue around the base. Very common on Sony PSU boards.
• Burn marks or scorched PCB tracks — dark discolouration around components.
• Cracked solder joints — look dull grey or fractured under a magnifying glass rather than shiny.
• Loose ribbon cables — especially the LVDS or flat flex cables between main board and T-Con. These are the most common cause of 5-blink codes.
• Arcing marks on inverter wiring — on older models, the high-voltage wires to the inverter board can arc against the metal chassis, causing 4-blink codes. Look for scorch marks on the insulation.

⚡ Power Supply Board — Detailed Diagnosis

Standby Voltage Test

Before full startup, the PSU must deliver a stable standby voltage to the main board. On most Sony models, locate connector CN6401 (or similar labelled connector) and measure with a multimeter (DC volts, black probe to chassis ground):

• Pin labelled 12V — should read ~12V DC in standby
• Pin labelled 5V or 3.3V — standby logic supply

If standby voltages are absent or wrong, the PSU has failed at the standby stage. Check the main fuse first (near the power inlet — label F6101 or similar, should read 0Ω continuity).

Full-Load Voltage Test (Technicians)

Connect only mains, main board, and power switch. Power on and measure each labelled output on the PSU connector block. Typical Sony LED TV PSU outputs:

If “BL ON” signal is present (3–5V from main board) but the VLED/24V output is absent, the PSU backlight driver section has failed — replace the PSU.

If “BL ON” signal is absent (0V), the main board is not requesting backlight activation — focus on the main board.

Fuse and Capacitor Replacement

• If the main fuse is blown, identify the short before replacing — check the rectifier bridge and MOSFET for shorts before fitting a new fuse.
• Bulging capacitors: replace with components of identical capacitance (µF), same or higher voltage rating, same or higher temperature grade (105°C preferred). Use quality brands: Panasonic, Nichicon, Rubycon.
• Always check capacitor polarity before soldering — reversed installation causes violent failure.

🖥️ Main Board — Fault Diagnosis

Common Main Board Symptoms

💾 Sony Bravia Software — Firmware Update & Factory Reset

Software problems can perfectly mimic hardware failures. Always exhaust software options before replacing boards.

Factory Reset

• Google TV models: Settings → System → About → Reset
• Android TV models: Settings → Device Preferences → Reset
• Older Bravia (non-Android): Home → Settings → Device Settings → Factory Data Reset → Erase Everything
• Default PIN: 0000

USB Firmware Update — Step by Step

This is the most important software repair tool for Sony TVs. Use it for boot loops, frozen logo screens, and persistent 5 or 8 blink codes before replacing any hardware.

1. Find your exact TV model number — on the sticker at the lower-left corner of the TV’s back panel (e.g. KD-55X9000H, KDL-50W829B).
2. Go to sony.com/en/support → type your model → Downloads → Firmware Update.
3. Download the firmware file to your PC.
4. Prepare a USB drive formatted as FAT32 (important — other formats may fail).
5. Extract the downloaded ZIP file and copy the firmware file (.pkg or similar) to the root folder of the USB drive (not inside any subfolder).
6. With the TV powered off, insert the USB drive.
7. Power on the TV — it will detect the firmware automatically and begin updating.
8. ⚠️ Do not press any buttons, turn off the TV, or disconnect mains during the update. Power loss during firmware install can permanently brick the main board.
9. After completion, the TV restarts automatically. Remove the USB drive.

Checking Current Firmware Version

• Google TV / Android TV: Settings → System → About → Build version
• Older Bravia: Press HELP button on remote → firmware version shown top-right corner of screen

📺 T-Con Board — Fault Diagnosis

T-Con failure is frequently misdiagnosed as panel or main board failure. Key symptoms:

• Horizontal or vertical lines across part or all of the screen
• Screen is split — top half correct, bottom half distorted (or vice versa)
• Washed-out, negative, or inverted colours
• Screen flickers but sound is completely normal
• TV powers on with backlight visible but no image at all

Before replacing the T-Con, always reseat the LVDS or flat-flex ribbon cables connecting it to the main board and panel. These cables are a common cause of intermittent and persistent T-Con-style symptoms. On 5-blink codes specifically, disconnecting the LVDS cable to the T-Con and observing whether the blink code changes is a useful diagnostic step — if it does, the T-Con or its cable is likely the fault.

T-Con board replacement is plug-and-play — no soldering required on most Sony models.

💡 Backlight / LED Strip Replacement

Backlight failure is the most common Sony Bravia hardware fault, typically producing a 6-blink code or a black screen with faint image visible under flashlight. Unlike board replacements, LED strip repair requires full panel disassembly:

1. Remove all boards and the back cover.
2. Carefully separate the LCD panel from the outer frame — use plastic pry tools, not metal.
3. Peel off the optical film layers (diffuser, prism sheets) in order — note their orientation.
4. LED strips are adhesive-mounted inside the backlight chassis. Replace the failed strips or the full set for reliability.
5. Reassemble in reverse — optical films must go back in the correct sequence and direction.

On older Sony models with CCFL backlights (pre-2012), the inverter board drives fluorescent tubes rather than LED strips. These carry very high voltages and the repair should be handled by a qualified technician.

📋 Quick Fault-Finding Decision Tree

• No power, no standby LED → Check mains cable and socket → Fuse on PSU → Replace PSU
• 2 blinks → Inspect PSU capacitors → Replace PSU
• 3 blinks → Check PSU standby voltage → Replace PSU or main board
• 4 blinks → Flashlight test → Inspect inverter wiring for arcing → LED strips or LED driver
• 5 blinks → Reseat all ribbon cables → Disconnect T-Con LVDS and re-test → USB firmware update → Replace main board
• 6 blinks → Flashlight test → Check BL ON signal voltage → Replace inverter board / LED strips / PSU
• 7 blinks → Cool down 30 min → Clean vents → Check fan → Inspect for PSU or main board shorts
• 8 blinks → Disconnect external speakers → Run 8-blink reset procedure → USB firmware update → Replace main board
• Boot loop / stuck on logo → USB firmware update → Forced USB recovery → Replace main board
• Black screen, sound OK → Flashlight test → If faint image: backlight / LED strips → If no image: T-Con or main board
• Lines / distortion → Reseat LVDS cables → Replace T-Con board

🔧 Tools Needed

• Phillips screwdrivers (PH1 and PH2)
• Plastic pry tools / panel opening picks
• Digital multimeter (DC/AC voltage, continuity, diode mode)
• Magnifying glass (for capacitor and solder joint inspection)
• Anti-static wrist strap (recommended)
• Soldering iron and desoldering wick (for capacitor-level repair only)
• Torch/flashlight (for the backlight test)
• USB drive formatted FAT32 (for firmware updates)

🛒 Finding the Right Sony Replacement Part

Always order using the exact part number printed on the original board — never by model number alone, as the same Sony TV model can use different board revisions depending on production run, region, and panel type. Photograph the part number sticker before removing any board.

💡 ElPartsBay tip: We stock a wide selection of tested used Sony main boards, power supply boards, and T-Con boards. Browse Sony TV parts in the shop →

❓ Need Help?

Post your symptoms in our Community Forum — include your TV model number, the blink code, and what you’ve already tested. Our community of repair technicians can help narrow down the fault quickly.