so this has been bugging me for a couple weeks now and i finally have time to sit down and look at it. my 7300 started making this crackling/popping noise when i key up, doesn't matter what band, doesn't matter what power level. even at like 5 watts into a dummy load it does it. the RF output looks clean on the scope, SWR is fine, but there's definitely something going on internally because you can hear it through the speaker too when monitoring with the built in receiver.

at first i thought it was the final PA section acting up but the power output is rock solid and consistent so i dont think thats it. my gut says its something in the audio chain or maybe the ALC circuit doing something weird. i did notice the noise is slightly worse when the mic gain is cranked up but it happens even with mic gain at zero so that rules out the mic preamp i think.

has anyone seen this on a 7300 before or know what to check first? i've had the lid off and nothing looks obviously burned or bulging. caps look fine visually at least.

had something similar on mine about a year ago, turned out to be a cold solder joint on the driver board. the 7300 runs pretty warm in that area and over time some of those joints can develop hairline cracks. i found mine by gently flexing the board with a wooden stick while transmitting and the crackling changed character when i pressed on a specific spot. reflowed about a dozen joints in that area and its been fine since. not saying thats definitely your problem but worth looking at before you start replacing components.

also check the internal antenna tuner relay contacts if you have the tuner enabled. those relays can arc internally and cause noise that sounds like its in the audio chain. try disabling the tuner entirely and see if it changes anything.

is it definitely on transmit only or does it also happen when youre just receiving? asking because i chased a crackling issue on a different radio for like two weeks thinking it was TX related and it turned out to be a partially failed electrolytic on the main audio board that only showed up under load. easy to get confused when youre monitoring your own signal.