Advanced Measurement Technology 273A, User Manual

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Model 273A Potentiostat/Galvanostat User’s Manual
Caution! The apparatus described in this manual may be damaged if it is set for operation
from 110 V ac and turned on with 220 V ac applied to the power input connector.
Fig. 2. Power Input Assembly
.
A detailed discussion of how to check and, if necessary; change the power-voltage setting
follows.
The Model 273A can operate from any of four different power-voltage ranges, 90-110 V, 110-130
V, 210-230 V, and 230-260 V, 48-62 Hz. Change from one voltage range to another is made by
repositioning a plug-in circuit card in the rear panel Line Cord/Fuse Assembly. Instruments are
ordinarily shipped ready for operation from 110-130 V ac, unless destined for an area known to
use a line voltage in a different range. If this is the case, they are shipped configured for
operation from the other range.
If necessary, the change from one range to another can be accomplished in the field. Changing
the voltage range or changing the line fuse should only be done by a qualified service
technician, and then only with the instrument disconnected from all sources of power.
Observing the instrument from the rear, note the clear-plastic "door" immediately adjacent to the
power cord connector (Fig. 2). When the power cord is disconnected from the rear-panel
connector, the plastic door is free to slide to the left, giving access to the fuse and to the voltage
selector circuit card.
The selector card is located at the lower edge of the fuse compartment. A number printed on the
upper surface of the selector card is visible without removing the card. The number is somewhat
obstructed by the fuse but can be read if the viewing angle is just right. This number indicates
the selected nominal line voltage. There are four numbers on the card, but only one is visible. In
other words, the card can be inserted in any of four different positions, and a different number
can be read in each. A table printed on the rear panel of the Model 273A adjacent to the
power-input assembly indicates the actual line voltage range for each number.
If the number showing is incorrect for the prevailing line voltage, the card will have to be
repositioned, as follows. The first step is to remove the fuse. When the lever labeled FUSE
PULL is rotated out and towards the left, the fuse will lift so that it can be easily removed. At the
front center of the circuit card is a small hole that serves as a convenient pry point. Needle-nose
pliers or a paper clip can be used as an aid in removing the board. With the board removed, four
numbers become visible: 100, 120, 220, and 240. Orient the board so that the desired number
(Table 1) will be visible when the board is inserted. Then insert the board into its connector. The
selected number should be the only one that shows. Be sure the board is securely seated in its
connector.