Strong carrier on transmit. #bitx40help

radioant@...
 

I set up my bitx40 for transmit and on key up I heard a strong carrier from the bitx40. The carrier was 20 over on monitor receiver.  No it wasn't feed back from the mic. I looked at the balanced modulator circuit on the board and discovered that D15 and D16 and the 100 ohm trim pot we're not in the circuit. But a dual diode D20 was there. Could someone explain this modification and if anyone else has had this problem. Will see if any DC is getting back into modulator.  Thank you Bob WB2TFG

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