A television not turning on is one of the most common TV complaints in 2026 — and one of the most misdiagnosed. Some fixes take five minutes and cost nothing; others involve high-voltage components that demand real caution. This guide ranks the four most likely causes from most to least common so you can diagnose the real issue before spending a cent.
4 Common Causes for a Television Not Turning On
1Power Supply Board Failure
The power supply board converts AC wall power into the multiple DC voltage rails the TV needs to operate. When it fails — due to thermal stress, surge damage, or component aging — the TV receives no usable power and will not turn on, even though the wall outlet is functioning. This is the single most common hardware cause of a dead television and should be the first internal component you investigate after completing the preliminary checks above.
Symptoms
- No standby indicator light whatsoever — the TV appears completely dead
- Standby light flashes briefly then goes out when you press power
- A faint clicking or ticking sound from inside the chassis when power is attempted
Care Plan
- Unplug the TV from the wall outlet. Wait a minimum of 30 minutes as a starting point — but do not treat this as a clearance to touch the board. Passive wait time alone is not reliable because bleed resistors may be degraded or absent, especially in a TV with a compromised power supply. Proceed to the discharge step below before touching anything.
- Discharge the large filter capacitors actively. Using an insulated resistor-based discharge tool (a 25,000-ohm, 10-watt power resistor with insulated test leads works for this purpose), touch the leads across the terminals of each large electrolytic capacitor on the power supply board. Hold for at least 10–15 seconds per capacitor until a multimeter reading across the terminals confirms voltage is at or near zero. Do not skip this step.
- Remove the back panel using a Phillips-head screwdriver with an insulated handle. Locate the power supply board — it is typically the largest board, positioned near the AC power inlet.
- Visually inspect the board for burnt components, discolored areas, broken solder joints, or a blown glass fuse. A blown fuse (usually a small glass or ceramic cylinder in a holder near the AC inlet) is the easiest fix — replace with an exact-specification fuse ($1–$5).
- If no fuse is blown and the board shows physical damage or fails visual inspection, note your TV’s make, model number, and chassis number (printed on the label inside the back panel), source a replacement board ($25–$120 depending on brand and model), and swap it in. If the new board does not resolve the issue, escalate to a professional — the fault may involve multiple boards or the panel itself.
Common Mistakes
- Relying solely on the 30-minute passive wait and then touching the board without actively discharging the capacitors. Degraded bleed resistors — plausible in a TV with a failing power supply — will not discharge capacitors on schedule.
- Installing a replacement board with a different revision number or voltage specification than the original. Always match the exact part number or verify compatibility with the TV model before purchasing.
2Blown Capacitors on Power Supply Board
Rather than full board failure, sometimes only a few electrolytic capacitors on the power supply board fail — bulging, leaking, or opening internally. This is an extremely common failure mode in televisions that have seen 4–8 years of use, because electrolytic capacitors degrade with heat cycling over time. Replacing individual capacitors costs a fraction of a full board swap and is within reach of anyone comfortable with basic soldering.
Symptoms
- Visible bulging, domed tops, or crusty brown residue leaking from the top or base of cylindrical capacitors on the board
- TV clicks on briefly and immediately shuts off (a protection circuit response to undervoltage from a failing cap)
- TV functioned intermittently before stopping entirely
Care Plan
- Unplug the TV, wait at least 30 minutes as a starting point, then actively discharge all large filter capacitors using a resistor-based discharge tool as described in Cause 1. Confirm each capacitor reads near zero volts with a multimeter before proceeding. Use insulated tools throughout.
- Remove the back panel and locate the power supply board. Examine each electrolytic capacitor under good lighting. Healthy capacitors have flat tops; failed ones have tops that are domed, cracked, or show leaking brown electrolyte material. Mark any suspect capacitors with a piece of tape before desoldering.
- Note the capacitor specifications printed on the body — capacitance in microfarads (µF), voltage rating (V), and temperature rating (°C). Order exact replacements or equivalents with equal or higher voltage and temperature ratings ($5–$30 for a full replacement kit from suppliers such as Mouser, Digi-Key, or Amazon).
- Desolder the failed capacitors from the board and test them if desired. Important: Capacitors must be fully discharged and completely desoldered from the circuit before capacitance testing — in-circuit testing produces false readings due to parallel circuit paths and can damage your multimeter. Visual inspection (bulging, leaking) is the primary diagnostic method; electrical testing is secondary and requires desoldering first. Note the polarity stripe on each capacitor before removal. Work in a well-ventilated area — solder flux fumes are a respiratory irritant with prolonged exposure. Use a soldering iron stand; never leave a hot iron resting on or near ribbon cables or board components. Keep the iron away from plastic connectors.
- Solder in the replacement capacitors, matching polarity carefully (the negative stripe on the capacitor aligns with the negative marking on the board). If the TV still fails to power on after capacitor replacement, the fault extends beyond these components — consult a professional for board-level diagnosis.
Common Mistakes
- Installing replacement capacitors with a lower voltage rating than the originals. A capacitor rated below the circuit’s operating voltage will fail rapidly or immediately.
- Testing capacitors for capacitance while they are still soldered to the board. Parallel circuit paths will produce readings that appear normal even on failed components. Desolder first, or rely on visual inspection.
3Main Board Failure or Firmware Corruption
The main board (sometimes called the logic board or T-con board, though technically separate components) handles signal processing, the operating system, and the startup sequence. If the firmware — the software stored on the main board’s flash memory — becomes corrupted, the TV may fail to complete its boot sequence and appear completely dead or get stuck in a restart loop. Physical main board failure produces the same symptom. Firmware recovery requires no disassembly at all and should always be attempted before opening the TV.
Symptoms
- Standby light is present, but the TV never powers on fully or immediately restarts
- TV powers on to a blank screen with backlight visible but no image
- TV was recently interrupted during a firmware update (power outage, unplugging during update)
Care Plan
- Attempt a firmware recovery via USB — do this first, before any disassembly. Search your TV’s exact model number along with “firmware recovery USB” on the manufacturer’s support website. Download the recovery firmware file to a USB drive formatted to FAT32, insert it into the TV’s USB port, and follow the manufacturer’s recovery procedure (this typically involves holding a button combination while plugging in the TV). This step is entirely non-invasive and resolves corrupted firmware without opening the TV.
- Perform a hard reset. With the TV unplugged from the wall, press and hold the physical power button on the TV chassis for 30 seconds. Note: this step drains residual charge from the low-voltage control circuitry and serves as a reset technique — it does not discharge the high-voltage bulk capacitors on the power supply board. After holding the button, plug back in and attempt to power on.
- If USB recovery and the hard reset do not resolve the issue, unplug the TV and actively discharge the power supply board capacitors as described in Cause 1 before proceeding. Remove the back panel using an insulated Phillips-head screwdriver. Identify the main board—it is usually the board with the HDMI, USB, and antenna inputs.
- Inspect for loose ribbon cables. Vibrations or heat can cause the wide, flat ribbon cables connecting the main board to the screen or the T-Con board to unseat. Gently flip the locking tabs, reseat the cables, and lock them back down.
- Replace the Main Board. If firmware recovery failed and cables are secure, the main board likely has a failed processor or flash chip. Source an exact replacement by matching the part number printed on the board (e.g., BN94-XXXXX for Samsung). Swap the board ($40–$400), ensuring all connectors are fully seated. If the TV still shows no image but has sound, proceed to Cause 4.
Common Mistakes
- Skipping the USB firmware recovery. Many main boards are replaced unnecessarily when a simple software “forced update” would have fixed the corrupted boot sector for free.
- Mixing up board revisions. Manufacturers often use different main boards for the same TV model depending on the month it was produced. Always match the part number on the board itself, not just the TV model number.
4Failed LED Backlight
Modern LED TVs use strips of light-emitting diodes behind the LCD panel to create the visible image. If one or more LEDs in the series fail (burn out), the TV’s protection circuit may prevent the unit from turning on, or the TV may turn on “blind”—where the sound works and the standby light is off, but the screen appears black.
Symptoms
- The “Flashlight Test” succeeds: Shine a bright flashlight directly against the screen while the TV is “on.” If you can see a faint image of a menu or a show, the TV is working, but the backlight has failed.
- The TV standby light blinks a specific error code (check your manual for “Backlight Error” codes).
- The screen flashes a logo for a split second before going black.
Care Plan
- Perform the Flashlight Test. This is the definitive way to confirm Cause 4 without opening the TV. If you see an image under the flashlight, the power supply and main board are likely healthy.
- Unplug and Discharge. As always, unplug the TV and actively discharge the high-voltage capacitors on the power supply board using your resistor-based tool.
- Access the LED Strips. This is a high-difficulty repair. You must remove the outer bezel, the LCD panel (which is extremely fragile and cracks easily), and the diffusion layers to reach the LEDs.
- Test the LEDs. Use a dedicated LED tester tool to check each strip. A single failed LED in a series will prevent the entire strip (or all strips) from lighting up.
- Replace the Strips. Replace all LED strips as a set ($20–$80) rather than just the failed one to ensure uniform brightness and prevent a repeat failure. Given the risk of cracking the screen during disassembly, professional labor ($120–$300) is highly recommended for this specific repair.
Common Mistakes
- Cracking the LCD panel. The screen is paper-thin and not reinforced once removed from the frame. If you flex it even slightly during the backlight repair, the TV is permanently totaled.
- Replacing only the “bad” LED. LED strips have a finite lifespan. If one has burned out, the others are likely close to failure. Always replace the full set.
