Kenwood TR-7400A Operating Manual page 12

Top side
L
L.
Fig. 10 How to Install the Tone Oscillator Module
4.6 DESCRIPTION OF UNLOCK INDICATOR
The TR-7400A has a protection circuit which prevents it
from radiating undesirable signals should the phase-locked
loop (PLL), which is employed for the frequency synthesis, Seen from the cord
be unlocked. If the protection circuit operates, the Unlock
Indicator located at the center of the front panel lights
red and stops the local oscillator, thus shutting the TR-
7400A receive and transmit operation down.
However, you should note that the PLL will work normally
even if the Unlock Indicator lights red momentarily
in the following cases: -
(a) TONE PAD Connector
1. The POWER ON Switch (1) is depressed and released.
2. The MHz, 100 kHz and 10 kHz Selector Switches ((9,
(19, (Ð) are turned, or the 5 kHz Offset Switch de-
pressed.
3. The microphone button is depressed or released when
the TX OFFSET Switch (12) is positioned at +600 or
—600 for repeater operation.
4. The TX OFFSET Switch 07 is shifted to +600 or
—600 during transmit.
Touch tone
The TR-7400A has a tone pad input for "Auto patch"
operation. If you use a tone pad on the market, connect the
(b) Connection of Touch Tone
supplied miniature plug from your tone pad.
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