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Well all the chips came in so I started to t-shoot again and found that I had no signal on pin 8 of IC3, or pin 10 either. ?Checked the 3.3v to IC1 and it was there so I swapped it out with one from

Thanks, Paul (and others) – I have been leaning toward the new caps. I have looked the board over and seen no mechanical anomalies, have checked all and reheated a few solder joints (the audio pot

I just had the same problem with little or no audio after the change. I replaced C21 with a 1uf electrolytic and C22 with *.1uf* electrolytic cap. Worked fine and no chirp. Don't know if the

Tx for your replies. I was talking about receiving, my bad. I have the U3S, with Rx module , OXO,GPS and a few other things.? . For testing the BPFs I used a 50ohm load on the output and connected

I've just finished the OCXO module kit and want to start the final test (calibration) phase. My U3S setup includes the Switched Relay board and 5W PA board.? To calibrate the OCXO I believe I need to

I had a volume problem too where the volume remained at full bore irrespective of the potentiometer setting. Resoldering its legs into the board fixed the problem. Even under magnified examination the

I'm driving a small speaker directly with mine. It's one of those designed to be used with a cell phone. ?I've plenty of volume with this setup. 73 Howard

David, As Jim was talking about receiving I was assuming he was actually referring to the RX module being used with the U3S, although he did not specifically say that. 73 Alan G4ZFQ

I had those batteries on hand from a previous QRP project.? The 5 place battery holder is from Parallax.? https://www.parallax.com/product/753-00007

I forgot to mention, when I tightened the screw holding the pc board in place, the board warped enough to undo a connection to the pot.? I could loosen the screw and get audio back. Dave, KI4PSR

I had a similar problem, once I put the QCX in a case I lost audio.? Turned out to be the volume pot solder connections to the board.I removed the pot, placed bare wires in each of the solder points,

By the way, I reduced the RX current by about 12 mA just by replacing R48 (270 ohm) with 820 ohms. The backlight was too bright for me anyway.? Karlis YL3JG

Hi. From memory, the U3S has low pass filters, not bandpass filters. If that's correct you can transmit a signal on any band lower then the one the filter is designed for. Along with a lot of

Tony, It certainly seems as if it is something you did. They are definitely 104? Try checking the voltages, maybe that will give a clue. 73 Alan G4ZFQ

Got my enclosure in the mail today, along with a couple of .1mf (104) caps to replace C21 and C22 to try to eliminate clicks in the keyer when I adjust the volume of the side tone. I completed the

Jim, The BPF should be quite sharp and attenuate signals outside to 20m band. But it is not a brick wall, strong signals on other frequencies will still be heard but should be much weaker. You get a

I don't have the enclosure yet, but I'm looking at 4-5 pin mini DIN or mini XLR connectors. Or you could always go with the 4 pin 3.5 mm jack socket.

Those batteries ought to last quite a while!

Hello everyone. I am very new to the forum. I have recently built the U3S kit and the 20m band filter. I tuned the filter with a signal generator and oscilloscope.? I can clearly see it attenuating

Good evening all, I just wanted to write a quick note and thank all those who have offered, both in-group and via personal email, to help me get my QCX40 back on the road. Someone has kindly offered