Maintenance
5-14 HF SSB Transceiver 9323/9360/9390/9780 Technical Service Manual
q Check the output levels of the prescalers IC9 pin 3 and IC12 pin 3. The
frequency should be approximately the VCO frequency divided by 64 [1
04-02972 only].
q Check IC9 and IC10 pin 11 are high (approximately 5 V) when locked.
q Check that the VCO control voltages on TP1 and TP5 are within the limits
as indicated on the circuit diagram (or TP1 and TP9 [1 04-03135]).
q Check that the Enable, Data and Clock pulses are present at the input of
synthesiser integrated circuits IC10 pins 10, 11 and 12 and IC13 pins 11, 12
and 13 when changing channels (or IC9 and IC10 pins 5, 6, and 7 [1
04-03135 and 08-05332]).
q If only VCO2 is unlocked and the previous checks appear correct, alignment
may be the cause of the failure. Re-set VCO2 (see page 7-11, VCO2 adjust).
PA failure
To optimise the amplifier performance, the PA output transistors are matched in
pairs by a letter code. Measurements in this area depend upon the matched pair of
transistors fitted and the frequency of transmission.
Table 5-5 is a guide to the peak-to-peak voltages expected at the specified points
in the PA circuit. They are given for 100 W PEP full power output when driven
with a two-tone input. For these tests the supply voltage should be 13.6 V and the
output terminated into a 50 Ω load.
Table 5 -5: Peak to peak voltages
Frequency
(MHz)
Battery
(Amps)
V15
(V PP)
V16
(V PP)
V21/V22
(V PP)
V23/V24
(V PP)
E CEC BCB
2.5 9.0 0.15 1.5 0.15 11.0 0.25 30 2.2
3.5 9.0 0.20 1.5 0.20 12.0 0.28 30 2.5
5.5 9.5 0.30 1.7 0.30 12.0 0.40 32 2.8
8.5 9.5 0.35 2.0 0.35 12.0 0.50 36 3.0
15.5 10.0 0.45 3.5 0.45 18.0 0.80 35 4.5
17.9 12.0 0.50 3.5 0.50 20.0 1.30 30 4.8
26.5* 10.0 0.40 3.3 0.40 12.0 1.00 36 3.5
* Measured at 80 W PEP.
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