Today when I turned on the radio it got stuck in calibration mode then displayed TIMEOUT and led is blinking red. Pulling the power then reconnecting did not help.
My 6500 had a similar problem two years ago. After a 'quiet' while, it booted up normally. However, if I then turned it off. Turned it back on immediately, it did the same "timeout" routine. Eventually, I returned it and there was a major failure in a component. Mine was under warranty and I did not get a printed report of the problem. Since then, it has worked flawlessly. de N5LN