Re: nouveau 75 Dave Cripe/Voltage Checks


W9GY <jeffw9gy@...>
 

I've made some progress on Q11 overheating, and 'crud' in the modulation on this unit.  Various bypass capacitors on Q11 seemed to help, but I didn't think that the FET was cool enough and the envelope didn't seem as clean as it should be.  So I decided to take a look at why the device was running with so much current.  To make a long story short, I paralleled R43 with a 470 ohm resistor. This lowered the drive to Q12 and thus reduced the excessive current through Q11.  Now the transistor runs cool.  There appears to still be sufficient modulation capability in both directions, and the spurious signals now appear to be gone.
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Jeff W9GY Calumet, Mi (UP)

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