MDX 200

[jammeejoe]

I have a MDX 200 that I don't think has been changed over. I need to know what to do to change to 11 meters. I have re-tuned the tank coils and got it to put out but it has a bad hum in the transmit. I have changed out the electrolytics and that didn't help. I am wondering if the oscillator tube is causing the problem. Any help would be appreciated. Thanks Ray

 

[nomadradio]

If the radio makes it key when you transmit, then it's been converted. Maybe it wasn't converted quite right, but that's a whole different question.

Never have seen written instructions for doing that.

Never really sat down and wrote it up for the help here, either.

There are some small electrolytics that filter the bias voltage and the power for the relays. If they fail, you could get a hum on your AM carrier that way.

A failed tube can do it, as well.

Or a simple wiring error. But they're hard to identify without a wiring diagram of some kind. Sure wish D&A had printed one before they went under forever.

73

 

[jammeejoe]

I have tested the tubes and found one shorted. I then changed all of them out but still has the hum (so bad you can hardly be understood). I will change out the smaller electrolytics and give that a try. By the way I also changed out the Z-14 chokes out to. Thanks a lot for the info See you later. Ray