Put the transmitter in SSB.
Mic gain 12 o clock position.
Inject a 1KHz tone at 3mv level to the MIC jack (pin 8 = mic input, pin 7 = ground)
Use a old amplified computer speaker, to trace the 1KHz tone, at the points below:
- Q1053 (M5207L01) pin 4,
- With a DC voltmeter, Q1053 pin 3, must be around 2.5 Volts, and changing when rotating MIC Gain,
- Q1053 pin 2, amplitude changes when rotating MIC Gain,
- Q1081 (BU4053BCF) pin 14,
- Q1038 (NJM2902M) pin 7,
- Q1038 (NJM2902M) pin 8,
- Q1081 (BU4053BCF) pin 15,
Please let us know your findings.
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Greetings from Erik Rothuis (PA2ER), Terborg Netherlands.