Samsung Galaxy S24 Ultra Error DISPLAY-GRAIN-MURA: Display Grainy Texture Low Brightness
Sub-pixel luminance non-uniformity across the Dynamic AMOLED 2X panel caused by hardware-level Low-Temperature Polycrystalline Oxide (LTPO) backplane threshold voltage (Vth) variations during low-current sub-10 nit driving states, exacerbated by software de-mura compensation curves.
Hardware Diagnostic Matrix
Spec Ref #f463982dRequired 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, sandpaper-like or canvas texture visible on solid dark gray backgrounds in low ambient light
- Visible micro-banding and uneven pixel brightness under 15% display luminance
- Color shifting and dirty-screen effect (DSE) across 30Hz-120Hz refresh rate transitions
Root Causes & System Failure Modes
LTPO thin-film transistor (TFT) threshold voltage (Vth) micro-variations across individual sub-pixels at low gate-source driving voltages (Vgs)
Sub-optimal factory optical de-mura Look-Up Table (LUT) calibration programmed in the display driver IC (DDIC) flash
Inadequate pulse-width modulation (PWM) low-duty cycle integration combined with Samsung Anti-Reflective Corning Gorilla Armor layer light scattering
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
Software Mitigation and De-Mura Calibration Verification
Check for official firmware updates (One UI 6.1 and later). Navigate to Settings > Display > Advanced Settings and adjust the 'Vividness' slider to increase color saturation. Disable 'Extra Dim' mode (Settings > Accessibility > Vision enhancements) as driving the OLED at sub-threshold current limits amplifies TFT mura.
Hardware Diagnostics via Service Menu
Open the Phone dialer and enter *#0*# to access Samsung Service Mode. Cycle through RED, GREEN, BLUE, and RECEIVER (White) diagnostic screens, followed by SUB TEST (Gray 5%, Gray 10%). Inspect if the grain persists across high-current states (>60 nits); persistent fixed-pattern noise confirms uncompensated hardware backplane mura.
OCTA FPCB and Display Rail Power Verification
Power down the device, remove the rear glass, midframe, and wireless charging coil. Inspect the OCTA display flexible printed circuit (FPCB) for unseated contacts. Measure main PMIC display rail voltages on the display connector: ELVDD (+4.6V) and ELVSS (-2.5V to -4.0V dynamically driven). Ensure ripple noise does not exceed 30mV peak-to-peak.
OCTA Display Assembly Replacement & Recalibration
If structural mura persists and DDIC LUT cannot normalize sub-pixel delta, replace the display assembly with a genuine Samsung Service Pack (Part # GH82-33633A). Reassemble the device and connect to Samsung GSPN / Odin diagnostic software to execute Display Calibration, writing unique factory optical de-mura coefficients to the DDIC.
Hardware Reset & Fault Clear Sequence
Controller ProcedurePrevention & Routine Maintenance Guidelines
- Avoid setting static dark gray themes while running the device at sub-5% brightness with Extra Dim enabled
- Keep firmware updated to ensure the latest DDIC de-mura lookup table algorithms are applied
Frequently Asked Diagnostic Questions
What does error code DISPLAY-GRAIN-MURA indicate on Samsung Galaxy S24 Ultra?
Sub-pixel luminance non-uniformity across the Dynamic AMOLED 2X panel caused by hardware-level Low-Temperature Polycrystalline Oxide (LTPO) backplane threshold voltage (Vth) variations during low-current sub-10 nit driving states, exacerbated by software de-mura compensation curves. In engineering telemetry, it indicates display grainy texture low brightness requiring circuit verification.
What are the primary triggers causing error DISPLAY-GRAIN-MURA?
Diagnostic bench telemetry isolates the following common root causes: LTPO thin-film transistor (TFT) threshold voltage (Vth) micro-variations across individual sub-pixels at low gate-source driving voltages (Vgs); Sub-optimal factory optical de-mura Look-Up Table (LUT) calibration programmed in the display driver IC (DDIC) flash; Inadequate pulse-width modulation (PWM) low-duty cycle integration combined with Samsung Anti-Reflective Corning Gorilla Armor layer light scattering.
How do I reset and clear Samsung error DISPLAY-GRAIN-MURA?
Perform a hardware diagnostic soft reset by pressing and holding Volume Down and Power buttons simultaneously for 10-15 seconds until the Samsung logo appears, clearing transient display driver cache. If the error status repeats immediately after clearing, discontinue clearing and test circuit continuity.
Can I safely resolve error DISPLAY-GRAIN-MURA 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.