I have been using my FTDX-3000 for several years and suddenly, in a contest, the rig power-cycled when I was transmitting on 20 meters. This happened a couple of times, and it needed immediate attention. I have found in the past that some radios would power-cycle when the input voltage/current was too low. I assume this happens during transmit because that is when maximum current is required from the power supply. I checked my power supply voltage, and that looked good. The day after the contest, I tried to transmit again on 20 meters and all seemed to be fine. But I know things can change with antennas, grounds, etc. So I continued to look for a power issue.

Fuses can starve the rig of needed current

I remember once in the past, that my fuses in the power supply cable could reduce current to the rig during transmit and cause power cycling. Online discussion disclosed that these in-line fuses and holders can be a problem. So I pulled the fuses and the contacts appeared to be tarnished and even had black spots in a few areas. I thought this could be the problem.

Dremel Tool to the Rescue

I used a Dremel tool to clean the fuse contacts on both fuses. They are much shinier now. I installed the cleaned fuses, and all seems to be working fine. Hopefully I was only removing tarnish and not plating on the contacts. I think the contact area should be shiny, so I will check back in a few weeks and see if there are any more issues. If this happens again, I will replace the fuses and/or the power cable. I have been told that the in-line fuse holders might really be the culprit.

Audio problem also Disappeared.

One other interesting thing was noticed. Just the past couple weeks, I have started to have RF on the Receive audio in certain Band/Antenna combinations when using this radio. This has really not been a problem before. That problem is suddenly GONE! Now I think this might be a good indication that the time is coming to clean the fuses again. Hopefully this problem does not come back.