Power On - Codan NGT 2010 RF Technical & Service Manual

NGT—Technical description (2011/2012)

Power on

Drawings
If the transceiver is off when the
to gate V9 resulting in the drain going low.
The PWR ON line passes via the handset cable to the Audio & Interconnect PCB
(2011)/Audio Interconnect & Data I/O PCB (2012) in the RF unit.
2011: Drawing
2012: Drawing
Control for the power relay on the PA PCB, which in turn controls the transceiver power,
is via latching relay K1. This relay is activated by pressing the
which grounds the PWR ON line in the handset, setting relay K1 via transistor V1.
Drawing 04-03369, or
Drawing
The PWR ON line goes to the power relay coil K200. If the polarity of the DC supply is
correct and below 16 V, V216 conducts and relay K200 energises, thus closing contacts
of K200 and connecting the DC supply to the transceiver.
If the DC supply voltage exceeds 16 V, zener diode D203 conducts, causing V215 to also
conduct and switch off V216, thus preventing K200 from energising.
Diode D205 prevents relay K200 from operating if the DC supply is reverse polarised.
The power input circuit is protected from high voltage transients by the voltage-
dependent resistor R261.
104
04-03125
04-03425
04-03499 (sheet 1)
04-03542
key is pressed, the +5.4 V standby voltage is applied
and 04-03499 (sheet 2)
NGT Transceiver System Technical Service Manual
key on the handset,