Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A405 Safari/7534.48.3)
Also ensure your coax, connections, and antenna are OK and presenting a proper load and no mismatch or high SWR to the transmitter. The TS2000 has protection circuitry that will disable TX in those conditions.
could be lots of things; but first it could be your power supply is shutting down not the radio? Turn the transmit wattage down as far as you can and try again. How many amps is your power supply? You need 22A minimum for the full power of that radio.