Larcon FMT-24, Technical Manual

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FMT- 25 VHF FM TRANSLATOR 862-09725
Issue 1A:
RF Enabled is indicated by Led D5 and is on when Tx is enabled.
Temp fault is indicated by Led D9 and is on when temperature is high.
PSU fault is indicated by Led D36 and is on when power supply is faulty.
RF fault is indicated by Led D7 and is on when RF power is low.
VSWR fault is indicated by Led D8 and is on when RF Reflected power is high.
A/C Supply is indicated by LED D31 and is on when A/C supply is present.
EXT DC is indicated by LED D32 and is on when dc supply (+24V) is present.
TL-ID is indicated by LED D10 and is on when ID Module is installed.
Front panel adjustments.
R5 adjusts the level of the Forward power via SK1.
Power supply.
The incoming power supply voltages are +22V (SK1 pin1 and 2), and –12V (SK1 pin
23). IC6 regulates the +12V supply and IC7 regulates the +5V supply.
v
FMT POWER SUPPLY PCB (980808)
A/C Input supply:
The a/c input to the power supply module is provided by an external 24V a/c winding on the A/C
Mains transformer. The winding is connected to
SK1 pin 1 and pin 3
. A Full-wave Bridge
rectifier
(D1)
is used to rectify the a/c input, with capacitors
C1
to
C9
providing the smoothing.
The resulting raw dc is routed via
Fuse F1
(3 Amp) and Isolating diode
D2
to
SK4. LED D4
indicates the presence of the a/c supply.
+24V dc supply:
The
+24V
dc supply is connected to
SK2 pin 1
with the return connected to
SK2 pin 2
.
The dc is routed via
Fuse F2
(3Amp) and Isolating diode
D3. LED D5
indicates the presence of
the dc supply.
The combined supply at
D2
and
D3
cathode provides the power to the RF PA module via
SK4
and also to the MAIN PCB via
SK3
.
SK5 provides an output for a +12V Fan.
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FMT RF PA Module (980801)