Frequency
Count
Using a frequency counter, monitor the injection frequency at pin 11 of the RF Module (1)
at the Mother Board track and adjust each channel by trimming the appropriate coil on the Rx
Oscillator Module (8) or (18) as follows:—
A,C and P8 Bands
—
Operating frequency less 10,7 MHz
E and M Bands
—
Operating frequency plus 10,7 MHz
TRANSMITTER ALIGNMENT
Transmitter Keying
The transmitter should always be suitably loaded at the Antenna socket and keyed only for
the time required to make an adjustment and to observe the reading.
Multichannel Equipments
If three or more channels are provided, the alignment should be carried out on the Centre
frequency channel. It should be noted that Transmitter Oscillator crystals and trimmers are
numbered from XL13 L13 (which correspond to Channel 1 crystal and trimmer) up to X L18 L18
or XL24 L24 for 6 — 12 — Channel Modules respectively. Set CHANNEL switch to appropriate
channel before adjusting an oscillator trimmer.
Multimeter
Unless otherwise stated, the multimeter negative lead should be connected to the negative
supply at TP1 of the Noise Limiter module (3). Connect positive lead to Test Point indicated in
the alignment chart.
Preliminary Checks and Adjustments — Transmitter (See CAUTION 3 in this section)
(a)
With the OFF/ON switch 14SA in the ON position check that the resistance between positive
and ground and negative and ground is greater than 1 MR.
Return OFF/ON switch to OFF position.
(b)
Connect RF output meter to antenna socket.
(c)
Ensure that all Tx Multiplier Module (10) inductor cores are flush with the top of the former.
(d)
Ensure that the loudspeaker is connected or the LS . leads are terminated with a 3R resistor
(3W).
(e)
At the Audio Module (9) set 9RV2 and 9RV3 fully anticlockwise.
(f)
Remove the PA Module (11). Transfer the 47R test resistor (R5) from Mother Board
parking pins to pins 1 and 3 exposed on the Mother Board by the removal of the PA
Module (11).
(g)
Connect PSU and set to 13,8V.
(h)
Switch on equipment and check that front panel is illuminated.
(j) Check pin 3 of 10V Regulator Module (16) for 10V +0,3, —0,2V. Key transmitter and check
that the red (Tx) lamp lights.
4.12
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