Re: QCX 50w amp receive problem


Check that all the connections on C1, C16, D3, D5 and associated components are good - reflow the solder connections. Using a DVM check the PCB traces between those components (I had problem with a broken trace on my 50W build).

With the unit powered up and on receive, Q5 drain (connected to R12) should be near supply voltage and junction on D3 and D5 should be near ground (zero V). At the same time, the anodes of D3 and D5 should read about plus 0.6 Volts.  If these conditions, aren't met, you have a problem somewhere in that circuit area.
Peter Lee

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