Re: Issues with QCX+ kit
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Hi Paul. Bruce is correct. The DC on the drains of the BS-170s will "look like" RF to the detector circuit even when no RF is present and the max reading that circuit will show is "5.2 watts" so you are just seeing the DC voltage on the MOSFETs. An oscilloscope is a better way to look at the waveforms there.? Sounds like lots of issues. I think you should start with measuring the voltages on the ICs ... again ... this time using an external DVM. The internal one does load down some of the voltages. You need to see approximately 2.5 volts DC at pins 1,2,3,5,6&7 of ICs 5,6,7 and 8, as well as pins 5,6&7 of IC9. Pins 1,2&3 of IC9 should be just under 5 volts and pins 1,2,3,5,6&7 of IC10 should be at a bit less than half the supply voltage. And of course pin 8 of all the OP Amp ICs above should see supply voltage and pin4 should show ground potential. Please do those measurements again and report the findings. I think we should work toward getting the receiver working first.? Since you said it does not receive or transmit I first thought to mention checking continuity through the lowpass filter but you indicated you did that. By any chance did you get to any of the alignment procedures yet? Just curious if you tried the bandpass filter alignment and if so, what results did you see? Thanks .. good luck .. 73 .. Ron On Mon, Jul 15, 2024 at 1:03?AM Bruce Akhurst via <bruce=[email protected]> wrote:
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Ronald Taylor