Another Galaxy schematic error?

[brandon7861]

If anyone wants to check this for me (no radio at work), I think there is an error in the AMC/ALC section. D33 comes off the 8v rail. Its 8v all the time. So why would the AMC signal from Q38 go there? I suspect that removing the red section and adding the green would correct the schematic. The digital transistor Q60 is nothing fancy, just a PNP transistor (for the PA switch) with a couple resistors inside. Thanks!

 

[BayouRadioAmplifier]

I have looked at that section of the MIC audio line before.
Q39 killing the MIC audio input. Not sure if that is a mistake.

usually the AMC/ALC is disabled on all the radios I
ever worked on.

But, I have seen other mistakes in RCI/Galaxy schematics.
such at the PLL circuit, to the varicap diode.

- - just did a quick look. on the DX-66V PLL varicap
diode D94 is messed up. But on the DX-44V it is correct.

in the transmitter RF output section on these radios - -
the MOSFETs are drawn incorrectly, as depletion mode devices,
when they are enhancement mode.
And the drain and source are incorrect. but we know they are
usually IRF520's and can only be installed correctly.

not sure if these are all official RCI/Galaxy schematics.

but it gets you "in the ballpark"

the computer drafter guys make mistakes. at various
employers of mine, I would politely suggest the correction to them.

 

[BayouRadioAmplifier]

I was not clear here -

I have looked at that section of the MIC audio line before.
Q39 killing the MIC audio input. Not sure if that is a mistake.

I meant. Q39 shorts out and kills the audio input
from the MIC audio, as it should, when triggered

But I am not sure if what you mentioned
is an error in the drawing.

 

[brandon7861]

You are right, I was looking at it wrong. It is not an error. Q60 cuts off all AMC/ALC traffic and limiter bias when PA is selected to get max audio to the amp. With the base of Q60 low (no PA voltage), it passes the limiter bias and AMC signals to Q39.

I will edit thread title.

Now I am second-guessing myself again. Although I misunderstood the PA switch operation and the limiter bias, it still makes no sense that the AMC voltage would go to a point with constant voltage. I still think the AMC follows the green path and I will have to check this weekend if I get time. I have one of these in the shed.