Samsung SCX-4521F Series - Abnormal noise; Defective Image Quality

Samsung Electronics
Service Manual
Troubleshooting
6-28
6.7.3 Abnormal noise
• Description There is noise from the ADF when copying.
Check and Cause Solution
1. Check the Scanner Motor, gearbox and rollers.
2. Check the Motor Driver on Driver PBA.
6.7.4 Defective Image Quality
• Description The copied image is excessively light or dark
Check and Cause Solution
1. Check shading profile.
2. Check the gap between original and scanner
glass.
3. Check printing quality.
1. Redo shading profile in the tech mode.
2. A gap of more than 0.5 mm can cause a blurred
image. Ensure rollers and cover close correctly.
Replace as necessary.
3. See "Print" troubleshooting.
1. Check for correct assembly of gears and motor.
Ensure no parts are fouling and there are no foreign
objects in the mechanism or scanner path. Replace
any worn parts
2. Replace the main PBA and ADF PBA in seguence.