Yaesu FT-900 Technical Supplement

Introduction to Servicing

This technical supplement provides crucial information for the maintenance and repair of the Yaesu FT-900 HF Transceiver. It focuses on detailed procedures for component replacement, circuit board access, and CPU resetting. Expertise in handling surface mount chip components is required for servicing this equipment. Please refer to the FT-900 Operating Manual for specifications, installation, and operation details.

Yaesu Musen Co., Ltd. is committed to technological improvement and reserves the right to update procedures without prior notification.

Key Features and Specifications

The FT-900 operates across a wide receiving frequency range (100 kHz - 30 MHz) and covers 160 to 10-meter Amateur Bands for transmission. Key specifications include adjustable power output up to 100 watts (25 watts AM carrier), various emission modes (USB, LSB, CW, AM, FM), and high sensitivity receiver performance. The document also details specifications for the optional ATU-2 Automatic Antenna Tuner and the MH-31 Hand-Held Microphone accessory.

Component Replacement and Access

Detailed instructions are provided for the replacement of chip components, including identification of common chip types (capacitors and resistors) and precise methods for removal and installation. The supplement also outlines procedures for accessing various circuit boards, such as the RF Unit, Local Unit, PA Unit, LPF Unit, and the ATU-2 Unit. Specific steps for bottom cover removal, top cover removal, and sub-panel access are clearly described with accompanying diagrams.

CPU Resetting Procedures

For troubleshooting functional issues, two CPU resetting methods are explained: Soft Reset and Hard Reset. Both procedures will clear all memory contents, returning the transceiver to factory default settings. The Soft Reset involves holding specific buttons while powering on, while the Hard Reset requires manipulating an internal backup switch.