Ramsey Electronics FX-440 Manual page 17

GUIDE TO PC BOARD
UO CONNECTIONS
In addition to primary interconnections required for jacks and controls,
etc., your FX-series Transceiver PC board provides additional access to
operating voltages and circuit features to make later customizing as neat
and easy as possible. All these points are plainly marked on the board
itsel.f and highlighted on the facing page, with a few other components for
orientation.
1.
PRIMARY CONNECTIONS:
PWR (near l20): + 12-15 volts DC from S1.
GROUND: - DC from battery or power supply.
SPEAKER: both connections near C37
MIKE: both connections (IN & GND) near notched end of U1
SQUELCH: two connections marked CW and W near C16
VOLUME: three connections marked IN, OUT, GND.
ANTENNA: Center of S0-239 connected at "RF OUT" near C71
CHANNEL SWITCH: Row of holes numbered 1 through 12. The switch
wiper (moving contact) is wired to + 5V near "1. •
EXT AUDIO: must be jumpered per options to enable pin 4 of J1.
2. TEST POINTS:
+ 12V, + av, + 5V, + aR, + aT permit checking for presence of those
voltages. + aR
=
Receive mode. + aT
=
Transmit mode.
TP1: For checking of VCO control voltage during alignment.
TP2: For checking VCO frequency with counter.
TP3: For checking U3 prescaler output with counter.
R103: + 7VDC at top lead shows locked PLL. 0 volts
=
problem.
3. OPTIONS:
+ 12V, GND, +av, + 5V, + aT, + aR: provide supply voltage for
accessories or modifications designed by you. + 5V is available
both near L 1 and near C102. + aT and, + aR are near 013, 014.
Jumper Options for Packet Operation: SPKR to EXT AUDIO: Speaker
level audio for packet (J1). DISC to EXT AUDIO: FM discriminator
output for packet. FSK to EXT AUDIO: True FSK demodulation for
packet.
RSSI: "Received Signal Stren,gth Indicator" output from U1.
COR: "Carrier Operated Relay• output from U1.
PL: Input point for audio tones (DTMF, CTCSS, etc.)
Binary Programming Holes: The row of holes alongside the Binary
Programming labels permits installation of ribbon cable for
external programming devices designed by the innovative amateur
radio community. switches or interfaces, or a row of internal DIP
switches.
FX-440
Ref. 15