User's Manual

M7X and M7R Page 5-5 Maintenance
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(4) Using Key 9 and Key 10 to scroll up and down the configuration list, highlight Reference Trim as
shown in Fig 5-3.
Fig 5-3 Reference Trim Selected
(5) Press Key 13 – Change, then use Key 9 and Key 10 to adjust the percentage figure, then press
Key 13 – Store.
(6) Check the frequency counter display. Keep repeating step (5) until the frequency counter reads
as close as possible to exactly 10.000 MHz.
(7) If an external reference is to be used with the radio, highlight Reference Select and select
External.
(8) Press Key 5 – Home.
(9) Disconnect the frequency counter.
Checking the ac and dc Change-Over
When both an ac and a dc input supply are connected to the radio, operation is normally from the ac
mains supply. Should the mains supply fail, operation automatically switches to the dc supply without any
interruption to service.
If both ac and dc input supplies are connected to the radio, carry out the following check:
(1) Confirm that both ac and dc supplies are connected to the radio. Ensure that the rear panel ac
and dc power switches are set to the I (on) position.
(2) Confirm that the front panel ac and dc indicators are lit, the display is lit, and the radio is
operational.
(3) Switch off the ac supply from its source.
(4) Check that the radio continues to operate from the dc supply and the front panel ac indicator is
unlit. Note that the BIT indicator flashes when the ac supply is switched off.