I have been troubleshooting my deaf QRP+ transceiver.? It works on Transmit with 4W out on CW and 2W out on SSB.? 100 uV on 20M gives about S-5 meter reading.? I can barely hear 1 uV.

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I thought it might be the First Mixer SBL-1, but I was cautioned that it might not be because the transmit would be bad also (mine isn’t bad).? This is after I pulled the board from the radio.? Well, I put it back in the radio and

Measured signal levels with my TEK 100 MHz scope and HP 8640B generator.

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Here are signal levels at several points in the circuit:

Antenna input was adjusted at 14.200 MHz for 20 mV. (one cm pk-pk).

Measuring at C40 after the BPF was the same 20 mV.? This input to the SBL-1 Mixer.

Measured on C41 4 mV.? This is the Mixer output and input to AMP. (-6 dB loss)

Measured Amp Output on C40 20 mV.?

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Interesting is that with 20 mV at the Antenna Input on 14.200 MHz ?I get about S-5 on the S-meter;

??????????????????????????????? with 20 mV at the Antenna input on 50.000 Mhz?? I get about S-5 on the S-meter. (same).

??????????????????????????????? And both signals are same volume.

My questions are:

Is the SBL-1 good or bad?

If it is bad, How do I get it off the board ???

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I need help to get my radio back in proper operation.? Can anybody help me?? If I am on the wrong track, then point me in the right direction?

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Thanks, Wes

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Sent from for Windows 10

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