MZ-805 L/C/R meter
3 INSTALLATION
Mains Operating Voltage
The operating voltage of the instrument is shown on the rear panel.
Should it be necessary to change the operating voltage from 230V to 115V or
vice-versa, proceed as follows:
1. Disconnect the instrument from all voltage sources.
2. Remove the 6 screws which hold the case upper to the chassis and
lift off, noting the flat cable connector positions.
3. Remove the 4 screws securing the power supply pcb to the chassis
and lift the pcb free.
4. Change the appropriate zero-ohm links beside the transformer on the
pcb:
Note that, if the change of operating voltage is accompanied by a
change of supply frequency, optimum common mode rejection of the
mains will be achieved by setting the internal 100/120Hz selection to
100Hz for 50Hz supply and 120Hz for a 60Hz supply. This is set by
the status of link LK2 which is situated immediately below the
oscillator module on the main circuit board. With no shorting link
fitted to the pins the frequency is set to 100Hz; if a shorting link is
fitted it is set to 120Hz. The factory setting for 230V operation is
100Hz and for 115V operation is 120Hz. If LK2 is changed from the
factory setting the unit will need to be recalibrated at the new
frequency setting (calibration settings for 100Hz and 120Hz cannot
be held simultaneously).
5. Refit the pcb to the chassis, ensuring all connections (especially
safety earth) are remade as before, and refit the case upper.
6. To comply with safety standard requirements the operating voltage
marked on the rear panel must be changed to clearly show the new
voltage setting.
7. Change the fuse to suit the new operating voltage, see below.
August 2002
Link LK4 only for 230V operation
Link LK3 and LK5 only for 115V operation
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