Model 2701 User’s Manual Basic DMM Operation 3-19
6. Observe the displayed reading. If the “OVERFLOW” message is displayed, select
a higher range until a normal reading is displayed (or press AUTO for
autoranging). For manual ranging, use the lowest possible range for the best
resolution.
7. To measure another amps channel, repeat steps 5 and 6.
8. When finished, press OPEN if there is a channel closed.
NOTE When you have an amps-only channel closed, you cannot select a non-amps
function. For example, if channel 21 of the Model 7700 is closed, you cannot
select the DCV function (“INVALID FUNC” displayed).
AMPS fuse replacement (front panel AMPS input)
WARNING Make sure the instrument is disconnected from the power line and
other equipment before replacing the AMPS fuse.
1. Turn off the power and disconnect the power line and test leads.
2. From the front panel, gently push in the AMPS fuse holder with a flat blade
screwdriver and rotate the fuse holder one-quarter turn counterclockwise.
3. Remove the fuse and replace it with the same type (3A, 250V, fast-blow,
5 × 20mm). The Keithley part number is FU-99-1.
CAUTION Do not use a fuse with a higher current rating than specified or
instrument damage may occur. If the instrument repeatedly blows
fuses, locate and correct the cause of the trouble before replacing the
fuse.
4. Install the new fuse by reversing the procedure above.
NOTE For the Model 7700 switching module and other similar modules that support
the amps function, there are solder mount amps fuses. See the Model 2701
Service Manual for fuse replacement information.