Ramsey Electronics FX-440 Manual page 121

position for any given channel. Remember that the Receiver
Frequency corresponds to a repeater's output and that you are
using + RPT or -RPT to match the repeater's input frequency.
There is no need for diodes in the Simplex, + RPT or -RPT on any
channel intended only for listening. Also, be aware that omitting
these diodes does NOT completely disable transmitting capability.
Be VERY careful and use common sense when monitoring
outside the ham band.
RECEIVER ADJUSTMENT AND OPERATION
At this point, we assume that all preceding assembly steps have been
completed for stages "A" through "H" and that Stages "M" and "TX"
associated with the transmitter have NOT been done. A jumper wire is
still in place between ·+SR" and • + 8V. • All IC's are installed except U4.
NOTE: If you already have done parts installation in stages M and TX, it
would be better to finish that work and follow the test and alignment
instructions provided in those sections. You can still test and use the
receiver section without damaging the transmit section if the directions in
Stage TX are followed exactly. In particular, do not install L 10, L9 or C60
until instructed to do
so.
Adjustment Procedure:
1. Check PC board carefully for missed connections, wire trimmings or
untrimmed wires bent down, etc.
2. Connect speaker and DC supply voltage.
3. Obtain or make a non-metallic alignment tool capable of adjusting C81.
4. Set frequency to the channel you selected for 446.00 MHz Simplex.
5. Turn on the unit and verify normal operation of squelch and volume
controls.
6. Connect an accurate voltmeter to TP1 and adjust L7 for 1.6 volts (1 to
2 volts is OK for right now). L7 is adjusted using a hot soldering
iron and gently moving the wire short slightly toward or backward
along the PC board trace. Move it a bit with the soldering iron,
then check your voltage AFTER the iron is moved away. If the
voltage is in the higher range, 2 to 3 volts, move the wire towards
the C43 end. If the voltage is low, (.2 to 1 volt), move the wire
towards the ground end of the trace. If your voltage is zero or
above 4.5 volts, something is wrong in the assembly and you
should not continue to adjust L7 - the problem is elsewhere.
Believe it or not, this is the only way such a circuit can be
constructed and designed at UHF. There is no such thing as a
FX-440
Assm. 61