Here is oscilloscope troubleshooting on the SSB distortion. We looked at the signal going into the WM8731 RLINEIN (at the cathode of D2). The signal was fairly noisy without even pushing the PTT. With the PTT active and the radio generating RF, the noise on the signal increased dramatically. ?One hypothesis is that the trace from the mic jack to the MIC pin on J1 (on the main board) goes right past the RF section of the radio. Could that be inducing RF into the signal?
Another note, when we touched (I swear we didn't push hard) the probe to D2, D2 fell off. As near as we could tell, it looks like one side may not have been soldered at all. It's a very small part, I will attempt to re-solder it, unless do you have a spare DE digital board?
What's the purpose of D2 and would D2 being missing allow for RF to get into the signal?
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73,
Mark, N8ME
Mark Erbaugh