Elegoo Resin Printer Exposure Fault — LCD or LED Fix

What Does This Error Mean?

Exposure fault on Elegoo printers means the printer can't expose layers correctly — either the LCD has dead pixels or zones, the UV LED array is failing, or the cooling fan for the LED has stopped.
Run a printer self-test from the touchscreen.
It tells you exactly which subsystem failed.
Most fixes are an LCD replacement (most common) or LED replacement (less common).

Affected Models

Elegoo Mars 3
Elegoo Mars 4
Elegoo Saturn 3
Elegoo Saturn 4 Ultra
Elegoo Jupiter

Common Causes

LCD dead pixels in the print area
LCD burned out completely (after 1500+ hours)
UV LED array partially failed (uneven exposure)
LED cooling fan stopped (overheating shutdown)
Power supply not delivering full voltage to LED

How to Fix It

Run the LCD self-test.

On the touchscreen, navigate to Settings → Tools → LCD Test.
This displays a series of test patterns (white, red, green, blue, gradients).
Look at the LCD through the vat (vat removed first).
Any black spots, lines, or dead zones in the test patterns indicate LCD failure.
Check the LED cooling fan.

Look at the fan grille on the bottom or back of the printer.
Run a print or LCD test and confirm the fan is spinning.
If silent, the fan has failed and the LED is overheating — that triggers exposure fault.
The fan is the cheaper fix; do this before assuming LED failure.
Run a single-layer test print.

Print a one-layer flat test piece (Elegoo includes test files).
After exposure, look at the cured layer.
If parts are uncured or partially cured, the LED is uneven.
If the entire layer cures but the print fails layer 2 onwards, the LCD has issues mid-print.
Check the LCD hours.

Settings → System Info shows LCD usage hours.
Most Elegoo monochrome LCDs last 1500–2500 hours before noticeable degradation.
If you're at or past that, replacement is normal end-of-life maintenance, not a defect.
Replacement LCDs are 50–150 USD depending on model.
Order parts as needed.

Elegoo sells replacement LCDs and LED arrays through their site.
LCD replacement is a 30-minute job with a screwdriver.
LED array replacement is more involved but documented in the Elegoo wiki.
Don't try to repair the LCD — they're sealed assemblies.

Frequently Asked Questions

How long should an Elegoo LCD last?

Monochrome LCDs in current Elegoo printers are rated for 1500–2500 hours of cumulative exposure.
Heavy users hit that within a year; hobbyists typically take 2–3 years.
Plan replacement as preventative — failed LCDs mid-print waste resin and create cleanup messes.

Can I tell if it's the LCD or LED that's failing?

The LCD test screen makes this easy.
If test patterns show dead zones, it's the LCD.
If test patterns look clean but prints don't fully cure, it's the LED.
If neither test reveals issues but exposure faults still occur, the cooling fan is throttling the LED.