Samsung Galaxy S24 Ultra Error DISP-MURA-S24U: Display Grain Mura Subpixel Issue
Non-uniform luminance output (mura effect) across the Dynamic AMOLED 2X panel caused by low-drive current variation in individual LTPS/LTPO subpixel thin-film transistors (TFT) at ultra-low nit values.
Hardware Diagnostic Matrix
Spec Ref #a00fa8dcRequired Diagnostic Tools & Instrumentation
Multimeter Probing Targets & Circuit Tolerances
Bench Calibrated ±5%| Test Point / Circuit | Target Nominal Spec | Expected State | Fault Condition |
|---|---|---|---|
| Main Logic DC Bus | 3.3V / 5.0V DC (±0.1V) | Stable DC Potential | <2.9V (Brownout / Sag) |
| Thermistor / NTC Sensor | 10kΩ - 100kΩ @ 25°C | Smooth Thermal Curve | 0Ω (Short) or ∞ (Open) |
| Safety Ground / PE Continuity | < 0.5Ω Resistance | Solid Earth Bond | > 1.0Ω (Floating Chassis) |
Common Symptoms & Fault Manifestations
- Fine sand-like or grainy texture visible across uniform dark gray or solid backgrounds at brightness levels below 10%
- Uneven luminance gradation and banding across horizontal or vertical sweeps in dark mode
- Flickering or noisy micro-contrast variations under low PWM duty cycle frequencies
Root Causes & System Failure Modes
Threshold voltage (Vth) dispersion in the LTPO backplane drive TFTs under ultra-low drive currents (<10 nA/subpixel)
Subpixel de-mura calibration table offset or corrupt factory gamma look-up table (LUT) in Display Driver IC (DDIC) flash
Hardware batch variance in the M13 organic emitter deposition layer thickness impacting low-luminance efficiency
High-Voltage & Mechanical Safety Isolation
Prior to opening access panels, disconnecting terminals, or probing wiring, perform complete lock-out / tag-out (LOTO). Disconnect all AC mains, DC string isolators, and lithium battery banks. Allow internal smoothing capacitors at least 3 to 5 minutes to dissipate stored residual energy below safe threshold (<30VDC).
Step-by-Step Diagnostic & Resolution Procedure
Diagnostic Mode & Mura Profiling
Dial *#0*# in the phone app to invoke Samsung Hardware Diagnostic Mode. Cycle through RED, GREEN, BLUE, and enter SUB-OLED test screens. Set screen luminance to 5% in a darkroom environment (0 lux) and evaluate panel threshold deviation using a high-density grayscale ramp (10-30 IRE).
Software LUT Calibration & Vividness Profile Override
Navigate to Settings > Display > Advanced Settings. Verify if 'Vividness' slider is available (One UI 6.1+). Adjust slider to step 2 to remap low-luminance gamma curves. Disable 'Extra Dim' (Settings > Accessibility > Vision enhancements) which drives the panel into unstable non-linear sub-threshold voltage states.
DDIC Gamma Table Reflash & Calibration Verification
Connect device via ADB or Samsung authorized service tool. Flash the latest firmware containing updated DDIC de-mura compensation profiles. If hardware mura persists beyond 15% delta E threshold across adjacent 64x64 pixel zones, hardware failure of the backplane is confirmed.
OCTA Panel Assembly Replacement
If mura exceeds optical tolerance standards, power down device, disconnect battery flex connector, and replace the complete Display OCTA Assembly (Panel, Digitizer, Midframe) with an inspected service part. Re-run Samsung factory optical calibration tool to flash panel-specific OTP (One-Time Programmable) de-mura coefficients.
Hardware Reset & Fault Clear Sequence
Controller ProcedurePrevention & Routine Maintenance Guidelines
- Avoid running continuous high-contrast static elements at peak HDR brightness to prevent uneven TFT threshold drift
- Keep firmware updated to ensure optimal PWM frequency driving algorithms and calibrated gamma LUTs
Frequently Asked Diagnostic Questions
What does error code DISP-MURA-S24U indicate on Samsung Galaxy S24 Ultra?
Non-uniform luminance output (mura effect) across the Dynamic AMOLED 2X panel caused by low-drive current variation in individual LTPS/LTPO subpixel thin-film transistors (TFT) at ultra-low nit values. In engineering telemetry, it indicates display grain mura subpixel issue requiring circuit verification.
What are the primary triggers causing error DISP-MURA-S24U?
Diagnostic bench telemetry isolates the following common root causes: Threshold voltage (Vth) dispersion in the LTPO backplane drive TFTs under ultra-low drive currents (<10 nA/subpixel); Subpixel de-mura calibration table offset or corrupt factory gamma look-up table (LUT) in Display Driver IC (DDIC) flash; Hardware batch variance in the M13 organic emitter deposition layer thickness impacting low-luminance efficiency.
How do I reset and clear Samsung error DISP-MURA-S24U?
Perform a soft panel reset by toggling developer option 'Disable HW overlays', clear system cache via recovery mode (Hold Volume Up + Power while tethered to PC), and perform a Display Calibration reset via service code *#2663# (TSP/TKEY firmware update). If the error status repeats immediately after clearing, discontinue clearing and test circuit continuity.
Can I safely resolve error DISP-MURA-S24U without specialized shop tooling?
This fault is graded as Intermediate difficulty with Medium severity. Standard diagnostics require an insulated digital multimeter and appropriate hand tools. Always observe high-voltage isolation procedures.