icom 400pro

Where does it get it's power supply from? I don't have any knowledge of icom units at all, but it sounds like it's not getting power (enough power, anyway). If, for example, you have it wired to some other existing power supply (eg: the hazard lights power supply), there may not be sufficient juice to fire the icom up properly. My suggestion would be to get power directly from the battery, via a fuse near the battery of course. Also, equally possible is a faulty earth connection. If you have it earthed to the bodywork, try running a ground wire to the NEG battery terminal.

Also, it's not simply a matter of removing the plug from the back of the unit and checking for available power with a multimeter as there may be 12 volts present, but the current may not be sufficient to to voltage drop when the unit is turned on.

assuming all 12v supply has been checked, cables to batt wiggled with a multi-meter attached etc.
don't know much about icoms either, but a handheld i own had the habit of going 'off'.
turned out to be faulty plug/wire in headset bit that made the radio go into 'programming mode'
your radio might be programmed thru the mic connection, so check all is good there.
if mic can be unplugged temp, see if it goes off while it is disconnected.( i think this is ok to do, but i will stand corrected)

Putting all other specs aside, my handbook does specify a 10A fuse in the supply line. It will play up if the fuse is a lot lower in spec...........

Bitman, we have ICOM radios in our work gear. The ICOM's have a low voltage turn off. I'd say you aren't getting the required voltage to the unit.

That's why the units typically turn off everytime you start the vehicle....because the voltage drops below the threshold. Then you have to push the button to turn them on again (PITA).

We had the low voltage turn-off fuction disabled on our work ones so that people didn't have to remember to turn the radio back on everytime they started a piece of gear.

Take it back to the place you bought it from and they should be able to disable that function....don't let them tell you it can't be done.

Bitman,

I'll have a bet on low voltage too.

We have a repeater here with 2 Icom 400's in it, and when it was powered by a wet cell deep cycle, would regularly turn off one of the radios. Had to turnoff the faulty radio, wait a bit, then turn it back on.

Put in a Panasonic Gel cell, a couple of years ago, and the problem has never re-occurred.

Go with the others suggestions, and wire the Icom direct off the battery.

Hooroo,
Bob.

bitman
I have read all the answers and none of them are hitting the nail .
It is in the settings , you have to go in and change a setting , very complicated procedure ,
Go to this website and download the manual,If you can't find the solution let me know and I have a practice run again with mine and write it down .

Instruction Manual


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thanks for you're help guys it was a bad earth have a good 1