I've had a catastrophic breakdown in two of my TYT radios. I've seen others have the same problem so I thought I'd pass along what I know. My TYT 9000 440 radio went crazy and displays random junk on the display screen and you can't make the radio do anything. You can't even turn it off. Now, my TYT 9000 220 radio has done the same thing. The problem happens when the radio is turned on and there is a negative power spike in the house power. Since I use a 60 amp switching power supply, there is an instant drop in voltage for about 1 second. For some reason that's all it takes to corrupt the microprocessor. What you end up with is a perfectly good radio that has no brains. Therefore you cannot operate it. I suggest that if you run a TYT 9000, you put a 12 volt battery between the power supply and the radio. If you get a sudden power drop, the battery will keep supplying the proper voltage to the radio and the radio shouldn't lose its brains. I think the brains are in the front panel and if you find someone who has a TYT 9000 that won't transmit, you might be able to use the front panel from it to replace the front panel of the broken one. I'm keeping mine just in case I can find a solution or a broken TYT that I can scavenge a front panel from.
