Re: More on troubleshooting.

Jerry Gaffke


10db is a difference of about one and a half S units on receive, might not be noticed.
But is a factor of 10 down in power on your wattmeter, a bit more obvious on transmit.

You say the VFO works, are you sure?
I'd compare T2-1 and T2-6 between bad board and good board., looking with a scope.

Amp at Q4 might be presenting a funny load to the diode ring mixer.
Maybe pull C43, replace it with a 100 ohm resistor to ground, scope across that resistor
looking for 12mhz energy.

If waveforms around the diodes look symetrical, they are probably ok.

On Sun, Jun 18, 2017 at 07:50 pm, KM4TRT wrote:
C41  (I miscommuicated) is the cap going from the rf amp into the filter string, where I get a good signal on my friends board.
I checked all the parts that you mentioned and every thing was ok .   Took out T2 and found nothing wrong.
I probably will pull out the diodes as I don't think I can check them in their configuration. Then T1.\
I don't know how else to approach.

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