One of the members of the Frontenac Radio Group, my local club, had an issue yesterday with his ICOM 7000.........the radio would turn off as soon as he modulated on transmit. After an incredible period of frustration checking coax connectors, RF feedback in the shack, too much mic gain, too much compression and reading the service manual for clues he ran across an article in QRZ that mentioned a possible voltage drop.
Interestingly, as soon as he spoke into the mic on full power (100 watts) the current should be about 15 to 25A and the voltage should remain constant at 13.8 to 14.0 volts, if not , the ICOM shuts down and then reboots in a few seconds.
The ICOM power cord has two (2) 30A inline fuses. The article suggested that one should pull them (they are auto style bayonet type) and check the lugs for any corrosion or water damage. He pulled both fuses and thoroughly cleaned the lugs and reinstated them back in the power cord. Voila, he had full power and the rig did not turn off.
It seems the ICOM is very voltage sensitive below 13 vdc and will automatically shut off. When he tried to power up the transmit mode there was a demand for high current and the resistive contacts made by the fuse blades dropped the voltage below 13 volts and the rig shut down.
So there you have it, an easy fix to a very frustrating issue. Hopefully Derek's experience will save you from learning some new swear words if this happens to you and your IC-7000.