Adjustments
7-14 HF SSB Transceiver 9323/9360/9390/9780 Technical Service Manual
45 MHz filter alignment (08-04962)
108-04962
There are two methods of aligning the 45 MHz BPF located on the Rx/Exciter
PCB:
• using an oscilloscope and a signal generator
• using a spectrum analyser with a tracking generator
Both methods are detailed in the following two sections.
Alignment—method 1
The following steps detail the alignment procedure using an oscilloscope and a
signal generator in Test mode.
q Select Test 4.
q Connect a 100 µF, 25 V electrolytic capacitor in series with an 820 Ω
resistor between TP1 and 0 V (negative of capacitor to 0 V).
q Unsolder sweep link S—D24/D25 and R69 (coarse lock VCO1). Sweep link
S is located below the VCO1 shield and below the yellow LED H1.
q Remove the shorting link parked on the two ground pins of link E–E and fit
to B–E of noise limiter TP202.
Fitting the link to B–E opens the noise limiter gate.
q Connect the signal generator, which is set to a frequency of 8.4 MHz ±
100 Hz and an output of 0.7 mV PD to the receiver input.
q Connect an oscilloscope with a 10X probe to TP201.
q Connect External Trigger input to TRIG Test Point on the PCB. Set the
oscilloscope to:
Channel one
20 mV per division using a 10X probe
Timebase
2 ms per division
Trigger External
Adjust the trigger for a constant sweep
q Adjust transformers T3 and T4 and inductor L30 for a minimum ripple
response (see Figure 7-2).
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