B&K Precision 1686A - Manual - Manual (Page 14)

14
MAINTENANCE
WARNING
The following instructions are for use by
qualified personnel only. To avoid electrical
shock, do not perform any servicing other
than contained in the operating instructions
unless you are qualified to do so.
FUSE REPLACEMENT
If the fuse blows, the power on LED indicator will not light
and the power supply will not operate. The fuse should not
normally open unless a problem has developed in the unit. Try to
determine and correct the cause of the blown fuse, then replace
only with a fuse of the correct rating. The fuse is located on the
rear panel (see Fig. 2).
LINE VOLTAGE
115V 230V
FUSE VALUE 4A 2A
LINE VOLTAGE CONVERSION
The primary winding of the power transformer is tapped to
permit operation from 115 or 230 VAC, 50/60 Hz line voltage.
Conversion from one line voltage to another is done by simply
changing the position of the LINE VOLTAGE SELECT switch
located on the bottom of the chassis. To convert to a different
line voltage, perform the following procedure:
1. Make sure the power cord is unplugged.
2. Turn the unit over (bottom up) and reset the LINE
VOLTAGE SELECT switch for the desired line voltage,
115V or 230V.
3. A change in line voltage will also require a corresponding
change of fuse value. Install the correct fuse value as
listed in the FUSE REPLACEMENT section.
ADJUSTMENTS
This unit was accurately adjusted at the factory before
shipment. Readjustment is recommended only if repairs have
been made in a circuit affecting adjustment accuracy, or if you
have a reason to believe the unit is out of adjustment. However,
adjustments should be attempted only if a 3-1/2 digit
multimeter with an accuracy of ±0.5% dcV or better (B+K
Precision Model 388A or equivalent) and a 0 to 2 Ω, 250 Watt
adjustable resistive load is available.
If readjustment is required, use the following procedure.
Locations of the electrical adjustments are shown in Fig. 6.
CASE DISASSEMBLY
1. Turn the unit over, bottom up, and remove the three
screws that hold the front bezel to the chassis.