Garmin GTX 328 Transponder Maintenance Manual

About this manual

This manual provides detailed instructions for bench technicians to test and repair the Garmin GTX 328 Mode S transponder. It covers disassembly and reassembly procedures, functional testing, troubleshooting, and component-level maintenance. The transponder is a non-diversity Mode S transponder designed for aviation use, operating on 1030 MHz and 1090 MHz frequencies. It supports Mode A, Mode C, and Mode S operations, including identification (IDENT) and altitude reporting. The manual includes wiring diagrams, test equipment requirements, and hardware modification levels. It is intended for authorized repair centers and technicians with access to Garmin’s technical support resources.

What's inside

• Description and Operation
• Special Test Equipment
• Troubleshooting
• Disassembly and Reassembly
• Testing
• Parts and Assemblies
• Assembly Drawings

Specifications

Frequently asked questions

What modes does the GTX 328 support?

It supports Mode A, Mode C, and Mode S operations.

Can the GTX 328 be configured to turn on via the aircraft master switch?

Yes, it can be configured so the aircraft avionics master bus can turn the unit on.