Unplug the radio DC lead and all other leads incl.There is no need to have PEP output of more than 100-110W PEP by the way. 1 I currently have a Yaesu 991 (not 'a' version) which I really like, but recently Ive got an itch to try something new and keep one as a backup radio. On a sidenote the peak to average ratio also improved. The PEP output power increased from 75-80W PEP to approx 140-145W PEP (14,5V DC input). My eye sight is not good enough to attempt to remove some tiny ass'd diodes from the board.
I 'think' it holds the frequency enough to meet MARS specs. I did only one of the mods that involves a jumper from C1509 to ground, because the other mod that involves a 10uF capacitor is reported to cause modulation issues on FM and AM. 1/17 Anyone know of a ham or a company that would be willing to do the Mars mod on an IC7100 I want to get into Mars operations and would like to use my IC7100. There are two published mods that are possible on this radio. Of course, there is no need to overdrive any linear amplifier, however Icom engineers have probably overdone it a bit on the conservative side on this radio (?). This causes the output power to not go above approx 75-80W (PEP) as measured on my LPA-100 wattmeter in PEP mode with 14,5V DC input. This radio is known for a very conservative approach to internal ALC on the power output.
I recently bought a second hand Icom IC-7100 HF radio for a reasonable price.