Changing Line Voltages
on the 40-A2
The internal power supply of the 40-A2 Loudness Monitor contains a dual-primary
power transformer that is normally shipped configured for 117VAC operation.
To reconfigure the meter for 230VAC operation (or back to 117VAC), you
will need to remove the meter from its enclosure.
Locate the power transformer on the circuit
board. Right next to the transformer are two resistors
marked 117V, and 1 resistor marked 234V (highlighted area
in illustration below).
If the two 117V resistor are stuffed in
the circuit board, the meter is set for 117V operation,
while if the single 234V resistor is in place, the meter
is set for 230V operation.
To change input voltage, simply remove
the resistors for the undesired voltage, and install the
resistor(s) for the desired voltage (the resistor(s) for
both ranges are 1 ohm).
Reassemble the meter and verify that the
AC line connector is appropriate to the new power mains