ENMET
Corporation
ISA-40 Oxygen Monitor
4
3.1.1 Converting to 220
V
AC
Power
The input of the transformer must be changed in order to accommodate 220
V
AC
power. This is accomplished by
changing the wiring between four standoffs located under a protective cover next to the transformer, shown in Figure 1.
The wiring configurations and the power supply schematics are shown in Figure 5.
To change power supply wiring of transformer form 110
V
AC
to 220
V
AC
, resolder the transformer standoff leads to the
appropriate configuration shown below. The materials required for this are a flathead screwdriver a soldering iron, 18
gauge (or larger) insulated wire and 60% tin/40% lead resin sore solder.
C
AUTION
:
This procedure should be performed only by personnel with electrical repair experience.
1.
Disconnect power from control unit.
2.
Remove instrument circuit board to access transformer standoffs on motherboard.
3.
Unscrew the cover-retaining screw and rotate protective standoff cover until standoffs are exposed.
4.
Unsolder one lead at a time and then resolder to desired configuration (shown below).
5.
Wipe up and remove excess solder.
6.
Rotate protective cover over standoffs and tighten screws and replace circuit board.
110 V
AC
Wiring
220 V
AC
Wiring
110 V
AC
Schematic
220 V
AC
Schematic
Standoffs
(1,2,3,4)
Standoffs
(1,2,3,4)
1
2
3
4
1
2
3
4
Transformer
Protective
Standoff Cover
Transformer
Protective
Standoff Cover