MTS DOES NOT ENDORSE THE ABOVE LINKS, ANGELFIRE ADDED THIS
ICOM 730/740
Poor Preamp relay, Lower Receive with preamp on
Preamp relay has tarnished contacts. You can replace the relay (every other year) or do this mod. 730, 740, (Most of the 740's have been updated by the factory)
Warc Band Update. This info is in the Instruction Manual, someplace and the service manual on page 4-2 (for the 730). Here are the methods. 740 WARC, 730 WARC
The 740 uses the same plastic trimmer caps but doesn't suffer from the premature failure. (usually)
740 Compressor switch failure (Tx power drops with compessor off or on)
The switch routes the I.F. for transmitt. No DC through the switch, so it tarnishes (yes this is a common theme)(the 740 uses IF compression, nice feature). It is simple to fix. Use this update 740