Most user complaints about the RMA 220 stem from misconfigured dip switches. Standard configuration for a 4-switch block:

Warning: When using Bridge Mode, connect the speaker to the Channel 1 positive (+) and Channel 2 positive (+) terminals only. Never use the negative terminals.

While many older commercial units

Before plugging in the JBL RMA 220, read these mandatory safety warnings derived from professional JBL documentation:

Your JBL RMA 220 typically includes a 3-year warranty for commercial installs (5 years for registered products).

To file a claim:

Contact:
JBL Professional Support (USA): (818) 894-8850
Email: prosupport@harman.com

If problems persist and the unit is under warranty, contact the retailer or JBL support with purchase details and serial number.