18.104.22.168. Power Conversion.
The Spectrophotometer can be used with 115 Vac line power, 220 Vac line power, and with batteries. The unit must be
set up for the type of power that is going to be used.
Electrical shock may occur if Spectrophotometer front panel is opened while connected to ac
power. Always unplug power cord from both spectrophotometer and external power source
before removing front panel. Using the Spectrophotometer when not set up for the proper type
of power may result in electrical shock. If electrical shock occurs, see medic.
Using the Spectrophotometer when not set up for the proper type of power may result in damage
to equipment. Always check to ensure that the power connections are as specified below before
Ac Power. 115 Vac or 220 Vac: Follow the steps below to set the unit for use with either 115 Vac or 220 Vac
external power sources (fig. 2-5).
Unplug the power cord from the spectrophotometer and the external power source and open the case.
Wavelength dial should be set to 400 to avoid damage to equipment.
Remove the sample cells(7) and meter scale cards(2). Set aside. Push the wavelength dial(8) as far
forward as possible so that the indicator is below the lowest reading (400) on the wavelength scale(8).
Loosen the two captive thumb screws(9) on the front panel. Lift the front panel and attached electronics up
and out of the case. Turn the front panel upside down and gently lay it on a clean flat surface.
An internal ac power cable is connected to the external power cord receptacle on the back wall of
the case. It has a plastic plug marked BC1 on the opposite end. The battery power cable is
connected to the bottom of the case. It has a plastic plug marked HC5 on the opposite end.
Before connecting, ensure that plug socket on cable and pins on circuit board are properly
For ac power, connect the plug(18) on the internal ac power cable(19) to the power supply circuit board(20)
A short (about 4 in. long) internal power cable(22) is permanently attached to the power supply board(20).
It has a plastic plug marked HC5(23) at the opposite end. Connect this cable to the amplifier circuit
board(25) at location BC5(24).
Change for 115 Vac or 220 Vac. The Spectrophotometer is supplied with two small, plastic, ac power-
select plugs (line voltage plugs). One is stamped 115V(26) and has two wire loops. One is stamped
220V(1) and has one wire loop. One plug will be stored in the well(3) with the meter scale cards(2) and the
other will be in place at BC4(27) on the power supply board(20). Insert the plug for the voltage to be used
(115 Vac or 220 Vac) at BC4(27).