BX-240 • 5
© Box 73 Amateurfunkservice GmbH 2017
Function Test
Before mounting the circuit board into its
case a brief test is required. So next first of
all, the three caps should be pushed onto
the push button switch and the now
mounted display plugged into the corre-
sponding sockets. The slider switch should
be in the off position (Fig. 8). Lastly two
1.5 V batteries should be attached, making
sure of the correct polarity, and the device
may be powered up using the slider
switch.
The display will briefly show the greetings
text, then the FA-VA4 switches to measur-
ing mode. Should the display remain blank
then all the previous soldering must be
checked and reworked if necessary. When
everything is working correctly the slider
switch should be turned
off
and the batter-
ies removed from their holder. The fully
built board can be seen in Fig. 9.
Assembly into the case
First of all the four rubber feet from the
underside of the case are to be fitted, it
may help to use some flat nosed pliers to
pull on the thin rubber nipple from the in-
side while slightly twisting the foot into
place, after which the excess rubber inside
the case should be trimmed with side cut-
ters to around 2 to 3 mm so that it doesn’t
interfere when the board is screwed into
the case.
The board is now inserted, with the socket
to the front, into the case sub assembly and
loosely fixed with four M3
¥
4 cylinder
screws in the corners. Then the BNC sock-
et should be fixed using the supplied nut
and toothed washer after which the assem-
bly screws may be tightened.
After installation, with due diligence to
correct polarity, of the batteries, the case
cover should be put on and fixed with four
countersunk M3
¥
4 screws. Lastly, the
supplied label should be stuck to the un-
derside of the device.
Your FA-VA4 is ready now and can be
used in an uncalibrated measuring mode.
Fig. 6: Display with backlight; shown here the
side with the six connections
Fig. 7: View of the 20 pin display contact strip
after assembly
8: Slider switch in
off
position
